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JUL  1  "^  1981 


A  MANUAL 


STRUCTURAL  BOTANY 


AN  INTEODUCTOEY  TEXT-BOOK  FOR  STUDENTS 
OF  SCIENCE  AND  PHARMACY 


^    / 


BY 


HENRY  H.  RUSBY,  M.D. 


PROFESSOR  OF  MATERIA    MEDICA  IN  THE   COLLEGE  OF  PHARMACY  OF  THE   CITY  OF  NEW  YORK    (COLr.MBI^ 

university)  ;   chairman   op  the   scientific   DIRECTORS   OF  THE    NEW   YORK   BOTANICAL 

gardens;    president    of    the    TORREY    BOTANICAL    CLUB;    PHARMACOGNOSIST 

OF  THE    UNITED    STATES    DEPARTMENT   OF   AGRICULTURE;    MEMBER 

OF  THE    COMMITTEE    FOR  THE   REVISION   OF  THE   UNITED 

STATES    PHARMACOPOEIA    SINCE    1890 


WITH  599  ILLUSTRATIONS 


LEA   &    FEBIGER 

PHILADELPHIA    AND    NEW   YORK 
1911 


Entered  according  to  the  Act  of  Congress,  in  the  year  1911,  by 

LEA  &  FEBIGER, 
in  the  Office  of  the  Librarian  of  Congress.     All  rights  reserved. 


PREFACE 


This  volume,  which  is  a  condensed  but  fairly  complete  introduction 
to  botany,  and  is  suitable  as  a  text-book  for  academic  or  collegiate 
students,  has  been  written  with  special  reference  to  the  needs  of  the 
first  year  student  of  pharmacy,  as  a  preparation  for  his  second  year 
work  in  pharmacognosy.  It  may,  therefore,  be  regarded  as  an  intro- 
duction to  pharmacognosy,  as  well  as  to  general  botany.  It  will  be 
followed  by  a  companion  volume  on  Commercial  Pharmacognosy. 

Pharmacognosy  may  be  defined  as  the  art  of  identifying,  valuing, 
and  selecting  drugs  of  vegetable  and  animal  origin.  It  is,  therefore, 
^not  a  distinct  science,  although  various  sciences  may  be  employed  in 
its  practice.  In  such  operations  as  taking  specific  gravity,  making 
microscopical  measurements  and  determining  the  characters  of  crystals, 
physics  is  utilized.  In  making  qualitative  tests  of  identity  and  purity 
and  determining  the  percentages  of  constituents,  chemistry  is  involved. 
In  determining  the  structural  characters  of  plant  and  animal  bodies, 
botanical  and  zoological  knowledge  is  necessary.  In  determining  the 
value  of  drugs  of  which  the  purity  and  strength  cannot  be  estimated 
by  any  of  these  methods,  we  may  have  recourse  to  physiological  tests 
on  animals,  or  pharmaco-dynamics. 

It  is  thus  apparent  that  the  entire  field  of  pharmacognosy  is  very 
broad  and  that  its  complete  working  involves  varied  classes  of  labora- 
tory operations.  The  extent  and  complexity  of  detail  that  have 
become  necessary  in  these  operations  have  required  their  consideration 
in  separate  departments  of  the  pharmaceutical  curriculum,  so  that  such 
branches  as  physical  and  chemical  testing  and  pharmaceutical  assaying 
have  been  established. 

The  number  of  drugs  of  animal  origin  in  general  use  has  become  so 
small  that  the  study  of  zoology  is  no  longer  deemed  essential,  and  it  is 
left  to  botany  to  contribute  by  far  the  greater  portion  of  the  instruction 
now  deemed  essential  as  a  preparation  for  the  study  of  pharmacognosy. 
Manifestly,  a  knowledge  of  structural  botany  is  the  only  scientific 
basis  for  the  examination   of   the  i)lant  body. 


VI  PREFACE 

Since  a  correct  knowledge  of  the  structural  relations  of  the  plant- 
parts  to  one  another  can  scarcely  be  gained  without  some  knowledge 
of  their  uses  in  the  economy  of  the  plant,  it  follows  that  at  least  the 
elementary  facts  of  plant-physiology  must  be  considered  in  connection 
with  its  anatomy. 

The  parts  of  plants  which  are  used  as  drugs  may  come  to  us  either 
in  their  entire  condition  or  in  such  large  fragments  as  to  be  capable 
of  examination  with  the  naked  eye,  or  in  the  crushed  or  powdered 
condition,  when  their  examination  requires  the  aid  of  the  compound 
microscope.  Even  in  the  case  of  the  whole  drug,  the  examination  will 
frequently  call  for  the  aid  of  the  microscope  in  determining  difficult 
questions  of  identity  or  quality. 

Commercial  Pharmacognosy  may  be  defined  as  the  application  of 
pharmacognosy  to  ordinary  commercial  operations.  It  includes  the 
examination  of  crude  drugs  by  growers,  collectors,  traders,  brokers, 
importers,  and  ordinary  purchasers  for  pharmaceutical  purposes. 
All  such  persons  should  be  qualified  to  subject  their  drugs  to  the 
most  complete  and  minute  examination,  or  should  employ  someone 
who  is  so  qualified;  but,  as  a  matter  of  fact,  this  is  probably  not 
true  in  more  than  one  case  in  a  hundred,  though  happily  this  propor- 
tion is  steadily  increasing.  In  all  others,  dependence  is  wholly  upon 
examinations  made  with  the  naked  eye,  or  at  most  with  a  pocket  lens. 
The  work  on  Commercial  Pharmacognos}"  will  be  designed  for  the  use 
of  all  such  persons  in  their  commercial  operations  with  drugs.  It  will 
deal  with  the  commercial  aspects  of  all  drugs  found  in  commerce,  their 
identity,  varieties,  grades,  and  qualities,  their  substitutes,  adulterants, 
and  imperfections,  their  trade  designations  and  relative  values. 
Although  designed  for  use  as  a  text-book,  it  will  be  especially  valuable 
in  its  commercial  adaptations. 

In  view  of  the  totally  different  methods  of  examination  involved, 
and  the  apparatus  and  other  facilities  required,  the  subjects  of 
vegetable  histology  and  of  microscopical  methods  and  technique  are 
omitted  from  the  present  work,  its  object  being  to  teach  the  student 
all  that  it  is  possible  for  him  to  do  in  the  examination  of  drugs  with 
the  naked  eye  or  with  the  pocket  lens. 

H.  H.  R. 


CONTENTS 


CHAPTER  I 
Fundamental  Considerations 17 

CHAPTER  II 

Anthology;  General  Nature  of  the  Flower 23 

CHAPTER  III 
Laws  of  Floral  Structure 36 

CHAPTER  IV 
The  Perigone 50 

CHAPTER  V 
The  Androecium 62 

CHAPTER  VI 
The  Gynaecium 70 

CHAPTER  VII 
The  Torus  and  Disk 81 

CHAPTER  VIII 
Dissection  and  Analysis  of  Flowers 86 

CHAPTER  IX 
Pollination  and  Fertilization 90 

CHAPTER  X 
Carpology;  Functions  and  Structure  of  the  Fruit 102 

CHAPTER  XI 
Classification  of  Fruits 116 


Vlll  CONTENTS 

CHAPTER  XII 
The  Seed 127 

CHAPTER  XIII 
General  Structure  of  Root  andStem .  136 

CHAPTER  XIV 
Extensions  and  Appendages  of  the  Stem 15;j 

CHAPTER  XV 

Classification  OF  Roots  AND  Stems 158 

CHAPTER  XVI 
The  Leaf 170 

CHAPTER  XVII 
Anthotaxy 199 

CHAPTER  XVIII 
Cryptogams 207 

CHAPTER  XIX 
Botanical  Classification  and  Analysis 21 S 

CHAPTER  XX 
Botanical  Nomenclature 222 

CHAPTER  XXI 
The  Collection  and  Preservation  of  Botanical  Specimens      ....     226 


INTRODUCTION  TO  PHARMACOGNOSY. 
STRUCTURAL  AND   DESCRIPTIVE  BOTANY 


CHAPTER    I 

FUNDAMENTAL  CONSIDERATIONS 

Organic  Bodies,  Organs  and  Functions. — Living  bodies  differ  from 
those  wliich  are  lifeless  in  their  al)ility  to  grow  by  converting  into  their 
own  substance  extraneous  and  dissimilar  substances,  as  seen  in  the  use 
of  carbonic  acid  in  the  ]:)roduction  of  starch  and  cellulose.  This  process 
is  called  Assimilation.  They  consist  also  of  more  or  less  distinct  parts, 
each  of  which  performs  special  work  differing  from  that  performed  by 
the  other  parts.  These  parts  are  called  Organs  or  ]\Iembers,  and  the 
special  work  which  each  organ  performs  is  called  its  Function.  Living 
bodies  are,  therefore,  designated  as  Organic  Bodies  and  the  part  of 
nature  composed  of  them  the  Organic  Kingdom.  The  term  "organic 
body"  is  usually  preferable  to  "living  body,"  as  it  applies  equally  well 
to  a  body  in  which  life  has  ceased  to  exist.  A  third  important  char- 
acteristic of  living  bodies  which  may  be  mentioned  is  their  power  to  give 
origin  to  other  independent  living  bodies,  which,  separating  from  their 
parent,  or  remaining  attached  thereto,  grow  into  a  resemblance  to  it. 
That  is,  they  possess  the  power  of  Reproduction. 

Organic  Matter. — The  assimilated  matter  of  organic  bodies  is  called 
Organic  Matter.  Organic  matter  may  be  living,  as  cytoplasm,  or  lifeless, 
as  starch.  It  may,  as  in  the  case  p/  the  starch,  be  prepared  for  future 
use  as  food,  or  be  for  the  construction  of  tissue,  as  in  the  case  of  cellu- 
lose, or  it  may  exist  as  disassimilated  matter  resulting  from  the  per- 
formance of  function,  as  the  poisonous  ptomaines  of  bacteria.  The 
latter  may  still  be  of  some  service  in  the  i)lant  economy,  as  are  volatile 
oils,  or,  perhaps,  be  entirely  useless. 

Plants  and  Animals. — Organic  bodies  are  of  two  kinds — ^\>getable 
and  Animal — and  are  respectively  denominated  Plants  and  Animals. 

Biology. — The  study  of  the  organic  kingdom  constitutes  Biology. 

Anatomy. — Biology  in  attention  to  the  structure  of  bodies  is  Anatom}'. 


f  ROPERTT  UBRAIf 


r.  ir 


18  FUNDAMENTAL  CONSIDERATIONS 

Physiology. — Biology  in  attention  to  functions  is  Physiology.  We 
have  therefore  both  animal  and  plant  anatomy,  and  animal  and  plant 
physiology. 

Botany. — Biology  relating  to  plants  is  Botany. 

Gross  and  Minute  Anatomy. — Owing  to  the  totally  different  methods 
of  examination  employed  in  the  two  cases,  it  becomes  of  the  greatest 
convenience  to  divide  anatomy,  in  practice,  into  two  parts.  That  part 
depending  upon  observations  which  can  be  pursued  without  the  aid  of 
the  compound  microscope  is  knowai  as  Gross  Anatomy.  That  which 
requires  such  aid  is  Minute  Anatomy,  or  Histology. 

Microscopical  Botany. — Applied  to  botany,  the  latter  is  commonly 
known  as  Microscopical  Botany,  a  term  which,  though  incongruous, 
possesses  the  excellent  merit  of  being  highly  convenient  and  generally 
expressive. 

As  the  study  of  botany  involves  the  use  of  physics  and  chemistry* 
it  is  apparent  that  when  so  applied  they  become  parts  of  botany,  just 
as  botany  becomes  a  part  of  physics  or  chemistry  when  applied  in  the 
pursuit  of  those  branches.  The  propriety  of  such  terms  as  "chemical 
botany"  or  "botanical  chemistry"  is  thus  explained. 

Departments  of  Botany. — The  departments  of  botany,  and  the  manner 
in  which  one  may  arise  from  the  necessities  of  another  and  contribute 
to  it,  may  be  illustrated  as  follows: 

Systematic  Botany. — It  being  understood  that  no  plants  are  now  in 
existence  which  existed  in  the  beginning,  all  having  originated  through 
changes  effected  in  some  manner  in  those  which  formerly  existed,  one 
of  the  great  objects  of  botanical  study  is  to  ascertain  the  genetic  rela- 
tionships which  exist  between  plants  and  to  constitute  such  a  systematic 
arrangement  of  them  as  shall,  so  far  as  practicable,  indicate  the  lines 
and  order  of  their  development  from  others,  that  is,  of  their  Phylogeny, 
This  department  constitutes  Systematic  Botany. 

Structural  Botany. — Since  such  classification  is  based  chiefly  upon 
structure,  it  is  necessary  that  there  should  be  a  department  known  as 
Structural  Botany. 

Physiological  Botany. — Before  the  facts  ascertained  by  the  struc- 
tural botanist  can  be  utilized  in  classification,  it  is  necessary  that  the 
relative  ranks  of  the  structural  characteristics  should  be  determined. 
Of  any  two  structural  characteristics,  that  which  was  first  developed, 
or  is  the  older  in  creation,  should  form  the  basis  of  the  primary  division 
of  the  group,  the  other  of  a  subdivision.  In  ascertaining  such  relative 
ranks,  a  consideration  of  the  uses  of  the  several  characters  is  of  great 


MEDICAL  BOTANY  19 

value,  so  that  Physiological  Botany  or  AVgetable  Physiology  is  brought 
into  service. 

Organography. — When  structural  botany  has  for  its  object  merely  the 
determination  of  the  organs  as  they  exist,  it  becomes  Organography. 

Organogeny  or  Morphology. — When  such  object  is  to  determine  the 
development  of  organs  through  the  transformations  of  others,  as  of  a 
petal  from  a  leaf,  or  a  tendril  from  a  branch,  it  becomes  Organogeny  or 
Morphology. 

Homologies  and  Analogies. — The  ancestral  organ  and  its  developed 
product  are  called  Homologues  of  each  other,  and  an  Homology  or 
Affinity  is  said  to  exist  between  them.  For  example,  the  leaf  of  a  plant, 
and  the  petal  of  its  flower,  which  we  assume  to  have  developed  through 
the  modification  of  the  leaf,  are  homologues  of  one  another.  When  they 
are  only  similar,  without  any  genetic  relationship,  they  are  Analogues 
of  each  other,  and  Analogy  exists  between  them.  Morphology  might, 
therefore,  be  defined  as  the  stud}^  of  homologies. 

Anthology  and  Carpology. — As  classification  has  been  based  very 
largely  upon  flower  structure  and  fruit  structure,  the  study  of  these, 
respectively,  has  been  dignified  by  the  titles  Anthology  and  Carpology. 

Phytography. — The  description  of  plants  in  such  manner  that  they 
can  be  recognized  therefrom  is  called  Descriptive  Botany  or  Phytog- 
raphy. 

Other  Departments. — Botany  has  also  numerous  departments  depend- 
ing upon  the  class  of  plants  under  study,  as  Phanerogamic  Botany,  the 
botany  of  flowering  plants;  Cryptogamic  Botany,  that  of  flowerless 
plants;  Mycology,  the  study  of  fungi;  Agrostology,  the  stud}'  of  grasses. 

Agricultural  Botany. — This  is  subdivided  into  a  number  of  different 
departments,  such  as  Agrostology,  or  Graminology,  the  study  of  grasses 
and  of  their  culture;  Horticulture,  the  study  of  garden  plants  and  of 
their  culture;  Floriculture,  Pomology,  and  Forestry.  Doubtless  a  ver\' 
large  and  important  department  will  yet  be  established  for  the  study 
of  the  culture  of  medicinal  plants. 

Medical  Botany. — This  term  is  self-explanatory  as  to  its  general 
nature.  In  use,  however,  it  should  be  more  strictly  regarded  than  is 
customary.  The  term  originally  included  all  botany  relating  to  medi- 
cinal plants;  but  with  the  development  of  Pharmacy  the  greater  portion 
of  what  was  once  comprised  in  the  former  term  has  naturally  and  per- 
manently established  itself  in  the  form  of  the  separate  department, 
Pharmaceutical  Botany.  Medical  Botany  properly  concerns  itself  with 
the  medicinal  properties  and  active  principles  of  plants,  and  the  deter- 


20  FUNDAMENTAL  CONSIDERATIONS 

mination  of  their  uses,  iiioluding  the  principles  (l)ut  not  the  practice) 
of  their  preparation  as  based  upon  such  facts,  and  their  chissification  in 
view  of  medical  considerations. 

Pharmaceutical  Botany. — In  its  widest  scope,  Pharmaceutical  Botany 
would  include  the  classification,  phytography,  histology,  distribution 
and  culture  of  medicinal  plants,  and  the  collection,  preservation, 
packing,  transport,  commerce,  identification  and  selection,  composition, 
and  methods  and  processes  of  preparation  for  use  of  the  drugs  derived 
from  them.  From  this  it  would  follow  that  the  pursuit  of  pharmaceu- 
tical botany  would  demand  a  thorough  knowledge  of  nearly  all  depart- 
ments of  scientific  botany.  This  conclusion  is  to  be  modified,  in  view 
of  existing  conditions,  in  important  directions.  The  pursuit  of  the 
study  to  such  an  extent  would  almost  necessarily  involve  the  a^'erage 
pharmacist,  at  least  in  this  country,  in  financial  failure,  through  the 
inattention  to  practical  afl^airs  which  would  ensue.  It  is  the  peculiar 
office  of  the  teacher  of  technical  science  to  place  its  practical  benefits 
within  the  reach  of  his  students,  while  relieving  them  from  attention 
to  the  greater  portion  of  the  field.  It  is  not  to  be  overlooked,  however, 
that  while  such  a  process  of  extensive  exclusion  is  possible,  utility 
requires  that  a  corresponding  degree  of  elaboration  shall  be  attained 
in  special  directions.  The  faithful  teacher,  moreover,  will  not  refrain 
from  urging  as  liberal  an  indulgence  in  extra-utilitarian  study  as  indi- 
vidual circumstances  will  properly  permit.  The  directions  in  which 
botanical  knowledge  is  most  useful  to  practising  pharmacists  will 
determine  the  most  important  requirements  for  botanical  study. 

Pharmacognosy. — The  identification,  valuation,  and  selection  of  drugs 
— that  is  to  say.  Pharmacognosy — constitute  the  principal  field  for  the 
exercise  of  botanical  knowledge  on  the  part  of  the  pharmacist. 

It  is  convenient  to  divide  botanical  pharmacognosy,  like  vegetable 
anatomy,  into  gross  and  minute,  the  latter  concerning  itself  with  those 
characters  which  require  the  compound  microscope  for  their  demon- 
stration. 

Subjects  Essential  to  Pharmacognosy. — Remembering  that  vegetable 
drugs  may  consist  of  the  entire  plant  or  of  any  one  or  more  parts  thereof, 
and  that  they  may  reach  the  pharmacist  in  any  condition,  from  that  of 
unbroken,  or  even  fresh,  to  that  of  a  fine  powder,  the  departments  of 
botany  necessarily  pertaining  to  pharmacognosy  and  materia  medica 
will  appear  as  follows:  A  knowledge  of  classification  or  systematic 
botany,  while  a  prime  necessity  in  medical  botany,  there  being  a  distinct 
co-relation  between  natural  classification  and  medicinal  value,  is  one 


ORDER  OF  SUBJECTS  21 

of  tlu>  less  practical  and  essential  elements  of  ])liannacentical  botany. 
Still,  it  aids  the  student  in  the  ai)i)licati()n  of  i)hytography  and  espe- 
cially in  understandinfj;  distribution,  and  it  serves  to  crystallize  and 
systematize  his  knowledge  of  groups  of  medicinal  agents.  A  good 
working  knowledge  of  phytography  may  be  regarded  as  the  leading 
essential.  If  the  drug  is  to  be  sought  by  the  pharmacist  in  nature,  he 
can  recognize  it  only  through  phytography,  whether  that  knowledge  be 
acquired  through  folk-lore  or  book-lore.  If,  on  the  other  hand,  he  seeks 
the  crude  drug  in  commerce,  he  merely  restricts  his  phytography  to  the 
plant-part  under  inspection,  and  so  far  from  being  by  this  consideration 
relieved  from  phytographical  labor,  its  requirements  are  the  more  exact- 
ing and  its  methods  the  more  refined,  as  the  recognition  and  estimation 
of  a  fragmentary  representative  becomes  more  difficult  than  that  of  the 
complete  individual.  As  "Phytography"  in  its  ordinary  employment 
is  about  equivalent  to  "the  study  of  the  manifest  organs  of  plants," 
or  of  their  gross  units  of  structure,  morphology  becomes  the  key  to  the 
situation. 

When  drugs  come  to  hand  in  a  comminuted  condition,  the  compound 
microscope  is  the  only  resource,  and  the  department  of  plant-histology 
becomes  the  foundation  of  work.  As  will  be  shown  farther  on,  the 
greater  portion  of  this  subject  can  be  passed  over,  but  that  portion 
which  receives  attention,  permitting  the  recognition  of  detached  tissue- 
elements  and  the  determination  by  their  examination  of  their  source, 
requires  observations  quite  as  careful  and  knowledge  quite  as  accurate 
as  are  called  for  in  any  other  portion  of  the  field.  In  the  New  York 
College  of  Pharmacy,  for  the  students  of  which  this  work  is  specially 
prepared,  the  use  of  the  compound  microscope,  and  the  subject  of 
histology,  are  separately  taught,  and  the  treatment  of  this  important 
subject  is  left  to  the  appropriate  department. 

Finally,  we  note  that  only  an  insignificant  portion  of  the  materia 
medica  includes  the  bodies  of  flowerless  plants,  so  that  the  great  division 
of  Cryptogamic  botany,  as  regards  its  detailed  treatment,  is  not  essential 
to  Pharmacognosy. 

Order  of  Subjects. — In  attempting  a  comparative  view  of  the  series 
of  plants,  it  is  unquestionably  well  to  begin  with  the  lowest  form  and 
follow  the  line,  or  rather  lines,  of  ui)ward  (kn-elo])ment;  but  in  gaining 
our  first  knowledge  of  the  structure  of  the  })lant  organism,  sound  and 
accepted  rules  of  pedagogy  require  that  we  begin  with  the  more  obvious 
characters  of  the  higher  plants,  and  pursue  the  analytic  method,  so  far 
as  the  special  conditions  of  the  case  will  ])erniit. 


22  FUNDAMENTAL  CONSIDERATIONS 

It  has  been  repeatedly  remarked  that  ])hint  hfe  is  a  circle  of  germina- 
tion, growth,  and  reproduction,  passing  again  into  germination.  It 
therefore  makes  little  difi'erence,  on  general  principles,  at  which  point 
we  enter  upon  our  series  of  observations.  Begin  where  we  wull,  we  must 
labor  at  the  disadvantage  of  requiring  more  or  less  knowledge  of  facts 
preceding  our  point  of  departure,  and  therefore  not  as  yet  possessed. 
In  special  cases,  however,  there  is  much  more  room  for  choice,  and 
there  are  many  reasons  why  we  would  advise  pharmaceutical  students 
to  commence  b}-  observing  the  organ  concerned  in  reproduction,  namely, 
the  flower. 


CHAPTER  II 

ANTHOLOGY:  THE  GENERAL  NATURE  OF  THE  FLOWER 

The  Phytomer. — In  order  to  accurately  understand  the  structure  of 
the  flower,  we  must  first  consider  the  general  characters  of  its  struc- 
tural units,  which  are  the  same  as  those  of  the  stem  upon  which  it 
is  borne  and  of  which  it  is  a  part.  These  are  well  displayed  in  a 
willow  twig  (Fig.  1),  presenting  a  main  stem,  with  perhaps  short 
branches  below  and  leaves  above.  These  leaves  are  found,  upon  exami- 
nation, to  arise  at  regularly  occurring  points,  thus  dividing  the  stem 
into  parts  which  are  seen  to  possess  definite  and  uniform  characteristics. 
In  common  language  these  parts  are  called  "joints,"  and  technically, 
Phj'tomers  or  Phytons. 

Units  of  Structure. — The  upper  portion  of  each  phyton  is  commonly 
somewhat  enlarged  and  it  possesses  the  power  of  giving  rise  to  three  new 
structures:  (1)  the  leaf  (a),  or  in  many  plants  a  circle  of  two  or  more 
leaves;  (2)  a  superimposed  phytomer,  continuing  the  growth  of  the 
stem  in  its  original  direction;  (.3)  a  branch  extending  the  growth  of 
the  stem  in  a  lateral  direction,  or,  if  there  be  more  than  one  leaf,  then 
a  corresponding  number  of  such  branches.  Upon  the  upper  portion  of 
the  stem  the  branches  are  seen  still  undeveloped,  and  in  the  form  of 
buds  (6).  The  bud  originates,  with  rare  exceptions,  at  the  point  where 
the  leaf  emerges  from  the  stem  and  upon  its  upper  side.  This  point  is 
known  as  the  Leaf-axil.  The  portion  of  the  phytomer  which  gives 
origin  to  these  three  structures  is  called  its  Node  (c).  The  portion 
intervening  between  two  nodes  is  called  the  Internode  (d).  The  inter- 
node  does  not  normally  possess  the  power  of  giving  origin  to  these 
new  parts. 

The  branch  is  found,  after  development,  not  to  differ  essentially 
from  the  stem,  so  that  a  branch  may  be  regarded  as  a  lateral  stem, 
secondary,  tertiary,  and  so  on.  In  noting'hereafter  the  development  of 
the  other  parts  of  the  plant  out  of  those  here  named,  we  shall  frequently 
find  the  latter  so  modified  that  we  shall  be  unable  to  recognize  them 
by  the  ordinary  methods  of  examination,  so  that  the  relative  positions 
which  they  occupy  will  prove  an  important  guide.     A  correct  under- 


24      ANTHOLOGY:   THE  GENERAL  NATURE  OF   THE  FLOWER 

standing  of  morpholo^n-  requires,  tiierefore,  that  we  keep  in  mind  the 
following  faets  relating  to  the  internode,  no(k',  U-af,  branch,  and  super- 
imposed phytomer. 

1.  Any  of  them  may  remain  more  or  less  undeveloped. 

2.  There  is  a  definite  and  regular  arrangement  as  to  position  of  the 
leaves  upon  the  stem  in  most  cases. 

3.  Several  leaves  and  as  many  branches  may  develop  from  one  node. 

4.  The  branch  normally  develops  as  a  bud  in  the  leaf-axil,  and  con- 
versely a  leaf,  in  some  form,  is  normally  at  the  base  of  each  branch  in 
its  rudimentary  condition. 


Fig.  1.  Leafy  twig  of 


willow,  its  phytomers  separated,    a,  leaf;  b,  axillary  bud;  c,  node;  d,  internode. 


5.  All  growth  developing  in  the  leaf-axil,  with  the  exception  of  hairs 
and  similar  appendages,  is  a  manifestation  of  the  branch. 

6.  All  organs  of  the  plant  which  w^e  consider,  except  the  root,  the 
hairs,  etc.,  are  constructed  of  the  above  parts  in  some  modified  form. 

Certain  necessary  qualifications  of  the  above  statements  can  be  made 
only  when  we  come  to  the  study  of  the  stem,  and  these  do  not  involve 
any  failure  to  understand  correctly  the  principles  of  anthology. 

Propagation  by  Nodes. — Before  proceeding  to  consider  the  forms  of 
structural  modification  of  phytomers  in  the  development  from  them  of 


fMOnRTY  LIBRABff 

J».  C  State  C#«««« 


PROPAGATION  BY  NODES 


25 


the  fl()\v(>r,  certain  iini)()rtiiiit  i)r<)i)erties  ])ertaiiiiii<i;  to  tlieiii,  in  addition 
to  their  abihty  to  inultii)ly  and  grow  as  above  indicated,  shouhl  receive 
attention,  in  onh'r  tliat  hiter  a  comparison  of  reproductive  methods  can 
l)e  instituted.  It  is  found  that  if,  in  the  case  of  many  plants,  a  stem 
be  laid  prostrate  in  the  soil,  its  connection  with  tlie  parent  not  destroyed 
(P'ig.  2),  its  nodes,  in  addition  to  jwoducing  branches  (a),  may  develop 
roots  (/;)  similar  in  structure  and  function  to  those  of  the  parent.  If 
now  the  phytomers  be  sei)arated  through  some  portion  of  the  internode, 
they  will  heal  the  wound  so  produced  by  the  formation  of  a  callus  (c), 
continue  to  grow  independently,  and  become  plants  similar  to  the  parent. 
Such  a  process,  here  of  artificial  production,  is  of  frequent  natural 
occurrence  and  is  called  Propagation.  It  is  seen  to  be,  in  this  case, 
purely  vegetative,  and  may  be  defined  as  the  production  by  vegetative 
processes  of  a  plant-body  growing  independently  and  separately  from 
that  from  which  it  was  derived. 


Fig.  2.  Propagation  by  layering,     a,  axillary  bud  developed  into  a  stem;  b,  adventitious  roots; 

c,  callus. 


Various  other  modes  of  stem-propagation  may  here  be  referred  to, 
and  it  may  be  remarked  that  the  process  is  not  confined  to  the  node, 
occurring  in  exceptional  cases  from  fragments  of  the  internode,  root, 
or  even  leaves.  The  phytomers,  instead  of  remaining  attached  during 
the  rooting  process  (Layering),  maybe  first  separated  (Propagating  by 
Cuttings).  The  cutting,  in  this  case  called  a  Scion,  may  be  inserted 
(Grafting)  or  a  bud  may  be  so  inserted  (Budding)  imder  the  bark  of  a 
living  stem,  or  it  may  be  caused  to  take  root  in  the  soil.  Propagation 
by  tul)ers  or  parts  of  them,  as  in  the  case  of  the  potato,  is  identical. 
It  may  be  remarked,  in  passing,  that  in  tlic  seed  itself  nature  resorts  to 
a  similar  method,  for  the  contained  embr\()  consists  of  one  or  more 


26      ANTHOLOGY:   THE  GENERAL  NATURE  OF   THE  FLOWER 


phytomers.     This   process  is,  however,  sexual,  and  is  called  Repro- 
duction. 

Composition  of  the  Stem. — Roughly  stated,  the  stem  may  be  said  to 
consist  of  three  portions:  (1)  A  framework  consisting  of  strands  of 
conducting  vessels  (54,  g),  associated  commonly  with  fibers;  (2)  among 
and  around  the  last  a  quantity  of  soft  non-fibrous  tissue;  (3)  a  covering, 
membranaceous  when  young  and  changing  greatly  with  age. 

Composition  of  the  Leaf. — All  these  parts  are  extended  into  the  leaf, 
the  first  existing  in  a  system  of  branching  ribs  or  veins,  the  second  as  a 
filling  in  the  meshes  of  the  former,  and  the  third  as  a  highly  developed 
skin-like  covering,  the  epidermis. 

Parts  of  the  Leaf. — Morphologically  considered,  the  typical  leaf 
(Fig.  3)  consists  of  three  parts  which,  like  those  of  the  stem,  will  be 
considered  in  detail  hereafter.  The  base  (a)  bears  the  Pulvinus  or 
organ  of  attachment  to  the  stem,  frequently 
extended  into  an  encircling  sheath,  and  upon 
either  side  a  membranous  expansion  (h)  called 
the  Stipule.  The  stem  of  the  leaf  (c)  is  called 
the  Petiole.  The  blade  {d)  is  called  the  Lamina. 
In  some  plants  an  additional  organ,  the  Ligule, 
develops  as  an  appendage  upon  the  face,  being 
a  modification  of  the  stipule  (Fig.  465,  A,h). 

Modification  of  the  Structural  Units. — If  we 
could  observe  the  phytomers  of  such  a  twig 
during  the  process  of  formation  in  the  bud 
(Fig.  4)  we  should  find  them  in  a  more  and  more 
rudimentary  condition  towards  its  apex  or  center 
until  we  reached  an  ultimate  growing  point  («), 
where  development  had  not  yet  manifested  itself. 
Yet  this  point  would  possess  the  power,  under 
proper  conditions,  of  continuing  the  process  of 
development  and  growth  of  phytomers.  It  therefore  may  be  said 
to  represent  a  certain  amount  of  vital  energy  or  potential  growth. 
Now,  our  fundamental  ideas  of  flower  structure  rest  upon  the  fact  that 
this  vital  energy  or  potential  growth  may  be  diverted  from  the  produc- 
tion of  phytomers  and  leaves  such  as  we  have  been  considering  and 
may  produce  in  their  stead  other  structures  in  which  resemblance  to 
and  variation  from  them  are  mingled  in  variable  proportions.  These 
new  structures  we  then  call  Modified  Phytomers  and  Modified  Leaves. 
The  student  should  dwell  upon  this  point  until  the  exact  meaning  of 


Fig.  3.  Leaf  of  willow,  a, 
pulvinus  or  foot;  6,  stipules; 
c,  petiole;  d,  lamina.  4.  Dia- 
gram of  longitudinal  section 
through  bud.  a,  the  growing 
point. 


THE  FLOWER  CLUSTER  IS  A   MODIFIED  BRANCH 


27 


these  terms  becomes  clear.  When  hereafter  he  encounters,  as  he  very 
frequently  will,  a  reference  to  some  organ  being  modified  or  transformed, 
it  must  never  be  understood  that  it  was  first  produced  and  then  changed. 
The  exact  meaning  is  that  the  change  takes  place  in  the  direction  or 
exercise  of  the  energy  which  is  to  ])roduce  the  modified  structure. 

Modification  Produced  by  Injury. — Such  a  diversion  of  energy  may  be 
caused  by  accident,  as  seen  in  the  so-called  "Willow-cone"  (Fig.  5), 
resulting  from  an  injury  inflicted  by  an  insect  in  depositing  its  eggs  in 


P 


8 


10 


Fig.  5.  Willow  twig  with  tip  transformed  into  a  gall-cone  through  insect  agency.  C.  Willow  twig 
after  fall  of  leaves.  7.  The  same  with  axillary  buds  enlarged,  in  spring.  S.  The  same  with  axillary 
buds  developed  into  (a)  female  flower-bearing  branches,  c,  scale  (modified  leaf)  from  one  of  the  nodes 
of  "a."  9.  Scale  with  its  axillary  bud  developed  into  a  flower,  consisting  of  a  pistil  only,  o,  the  stipe; 
6,  the  ovary;  c,  the  style;  d,  the  stigmas.  10.  Longutidinal  section  through  willow  pistil,  a,  placenta; 
h,  ovule. 

the  center  of  a  bud.  A  portion  of  the  structures,  ha\ing  been  originated 
before  such  injury,  will  reach  a  partial  development,  but  further  pro- 
duction is  checked  and  a  distorted  product  results. 

Bud-scales  are  Modified  Leaves. — In  the  cases  which  we  shall  have 
to  consider  the  modification  dates  from  an  earlier  stage  and  is  natural 
and  physiological,  instead  of  pathological,  as  in  the  case  of  the  willow- 
cone.  Fig.  6  represents  a  twig  after  the  fall  of  its  leaves  in  the  autumn. 
Each  bud  is  seen  protected  by  its  lowest  leaf,  permanently  enlarged, 
and  developed  into  a  covering  scale.  At  the  base  is  seen  the  scar  of  the 
leaf  in  the  axil  of  which  the  bud  was  developed.  Fig.  7  illustrates  the 
twig  in  the  spring  after  early  growth  has  enlarged  the  buds. 

The  Flower  Cluster  is  a  Modified  Branch. — In  Fig.  8  (a)  the  covering 
scale  has  fallen,  the  branch  has  developed  to  a  length  of  an  inch  or  so, 


28      ANTHOLOGY:   THE  GENERAL  NATURE  OF   THE  FLOWER 

and  its  structure  can  be  seen  to  consist  of  a  great  number  of  very  short 
phytomers,  each  of  the  crowded  nodes  bearincf  a  scale  (c)  and  in  its 
axis  (Fig.  9)  a  peculiarly  shaped  body  (a,  b,  c,  d).  These  bodies,  as  we 
shall  soon  see,  are  flowers,  and  this  entire  bunch  is  a  flower  cluster. 
That  the  scales  are  modified  leaves  is  proved  not  only  by  their  position, 
as  pre^•iousl^'  explained,  and  to  be  further  explained  in  our  study  of  the 
leaf,  but  by  the  fact  that  in  exceptional  cases  the  branch  will  produce 
them  in  a  form  intermediate  between  that  of  a  scale  and  of  an  ordinary 
leaf  (Fig.  13,  a). 

Each  Flower  of  the  Cluster  is  a  Modified  Branch. — Such  being  the  case, 
anything  produced  in  their  axils  must,  according  to  the  same  laws  of 
position,  be  modified  branches.  We  must  therefore  regard  the  flower 
shown  in  Fig.  9  in  the  axil  of  the  leaf,  as  a  modified  branch,  one  of  a 
great  many  produced  upon  the  parent  modified  branch  shown  in  Fig.  8. 
How  profound  is  the  modification  which  has  taken  place  in  the  latter 
can  be  appreciated  from  a  consideration  of  its  reduced  size,  for  it  is  now 
approximate!}^  full  grown.  The  great  number  of  phytomers  upon  it, 
had  they  reached  the  form  and  extent  of  development  reached  by  those 
in  Fig.  1,  would  have  produced  a  branch  many  feet,  or  even  yards,  in 
length,  whereas  in  their  present  form  they  will  produce  a  structure  only 
an  inch  or  two  long.  As  we  shall  soon  see,  increased  complexity 
of  structure  has  replaced  the  greater  amount  of  tissue-growth  of 
the  leafy  branch,  a  cluster  of  flowers  having  been  produced  in  its 
stead. 

The  Flower  Explained  and  Defined. — Examining  now  the  little  modified 
branch  (Fig.  9)  taken  from  the  larger  branch  (Fig.  8,  a),  we  observe 
that  it  presents  two  uniform  portions  or  halves,  united  into  a  single 
body  except  at  the  tip,  where  they  are  separate.  In  exceptional  cases 
we  find  this  separation  extended  downward,  perhaps  even  to  the  base 
of  the  body,  and  each  of  the  separated  portions  expanded,  formed  and 
veined  very  much  like  a  small  leaf,  which,  in  fact,  it  is.  The  little  branch, 
a,  b,  c,  d,  is  thus  to  be  regarded  as  bearing  two  leaves  which  have  been 
developed  in  a  united  condition.  Upon  dissection  (Fig.  10)  the  body 
thus  formed  from  these  two  leaves  is  found  to  be  hollow  at  one  portion, 
containing  two  slight  projections  upon  its  inner  wall  (a),  and  upon  these 
a  number  of  minute  rounded  bodies  (6),  If  allowed  to  develop  and 
mature  under  the  requisite  conditions,  we  should  find  that  these  bodies 
had  become  seeds.  The  structure  ])roducing  them  we  now  see  to  be  a 
branch,  so  modified  as  to  produce  seeds,  and  this  constitutes  our  definition 
of  the  flower. 


THE  PISTILLATE  OR  FEMALE  FLOWER 


29 


Some  Flowers  are  Imperfect. — It  does  not  follow  that  because  con- 
structed for  the  production  of  seeds,  a  flower  is  always  capable  of  per- 
forming this  office  independently,  and,  indeed,  such  is  not  the  case  with 
the  flower  under  consideration,  which  is,  therefore,  an  Imperfect  ore. 

Sex  and  Sexual  Reproduction.- — INIinute  microscopical  examination 
discloses  within  the  bodies  which  are  to  become  seeds,  minute  structures 
called  JNlacrospores,  which,  after  germination  and  growth  in  that  i)lace, 
produce  cells  comparable,  in  their  essential  characters,  to  the  ova  of 
animals,  and  requiring  a  similar  fertilizing  process  to  cause  their  develop- 
ment.* Flowers,  or  at  least  certain  of  their  products,  are  thus  seen  to 
possess  sex  and  to  be  capable  of  performing  sexual  reproduction,  or 
reproduction  proper.  Commonly,  both  sexual  parts  are  present  in  one 
flower,  and  of  these  the  female,  the  2-leaved  branch  here  considered, 
and  in  this  case  all  that  there  is  to  the  flower,  is  called  the  Gynaecium, 
frequently  represented  by  the  symbol  G. 


Fig.  11.  Willow  twig  with  axillary  buds  developed  into  (a)  male  flower-bearing  branches.  12.  Scale 
(modified  leaf)  from  11,  a,  with  its  axillary  branch  developed  into  a  male  flower  consisting  of  two 
stamens,     a,  position  of  node;  b,  scale;  c,  filament;  it.  anther.     13.  .Abnormal  willow  twig,  the  scales 

(o)  of  its  flower-bearing  branch  intermediate  between  the  ordinary  form  and  the  leaf. 


The  Gynaecium  is  Composed  of  One  or  More  Pistils. — In  Fig.  47,  the 
gynaecium  consists  of  fl\c  such  bodies,  and  in  other  flowers  it  consists 
of  various  numbers.  One  of  them  is  called  a  Pistil,  so  the  gyn;;ecium 
may  consist  of  but  one,  or  of  any  number  of  pistils. 

The  Pistillate  or  Female  Flower. — This  flower  (Ing.  9)  possesses  only 
the  gynaecium,  and  is  therefore  often  s])()ken  ( f  as  a  "Female  Flower," 
technically  a  Pistillate  flower,  and  indicated  by  the  .-symbol    •.. 

*  For  an  explanation  of  this  subject  see  Chapter  IX. 


30      ANTHOLOGY:   THE  GENERAL  NATURE  OF   THE  FLOWER 


Fig.  14.  Diagram  representing 
transverse  section  through  anther, 
o,  theca,  containing  pollen;  6,  con- 
nective; c,  locellus.  15,  alder  twig. 
o,  pistillate-flowered  branches;  b, 
staminate-flowered  branches. 


The  Staminate  or  Male  Flower. — Before  considering  the  structure  of 
the  pistil  we  will  examine  a  "JNIale  Flower,"  borne,  in  the  case  of  the 
willow,  upon  a  plant  which  produces  no  pistillate  flowers.  Fig.  11 
illustrates  branches  (a)  crowded  with  male 
flowers  each  (Fig.  12,  a),  as  before,  in 
the  axil  of  a  scal^  (6).  In  this  case  the 
two  modified  leaves  forming  the  flower  are 
entirely  separate  and  the  hollow  portion  of 
each  {d)  is  small,  borne  at  the  summit 
of  a  stem  (c)  and  filled  (Fig.  14)  with  a 
great  number  of  minute  rounded  bodies. 
These  correspond,  though  of  the  other  sex, 
to  the  macrospores  which  we  have  found 
the  pistillate  flower  to  produce,  and  they 
are  called  IMicrospores — in  flowering  plants, 
Pollen-grains,  They  possess  the  power  of 
germinating,  growing,  and  producing  Male 
Cells,  comparable  to  the  spermatozoa  of 
animals,  and  requisite  for  the  fertilization  of  the  corresponding  egg- 
element  produced  by  the  macrospores. 

The  Androecium  is  Composed  of  one  or  more  Stamens. — The  male  por- 
tion of  a  flower  is  called  the  Androecium,  frequently  indicated  by  the 
symbol  A,  and  it  consists  of  one  or  more  Stamens,  in  this  case  of  two. 
As  this  flower  consists  only  of  androecium,  it  is  known  as  a  Staminate 
Flower,  indicated  by  the  symbol  d. 

The  Sporophyte,  Sporophyll,  and  Sporangium. — We  have  now  seen  that 
both  the  stamen  and  the  pistil,  homologues  of  leaves,  exist  for  the 
production  of  spores.  A  modified  leaf  producing  spores  is  called  a 
Sporophyll.  Both  the  stamen  and  the  pistil  form  hollow  bodies  for 
containing  one  or  more  spores.  Such  a  spore-case  is  called  a  Sporangium 
or  Sporange.  A  plant  producing  sporophylls  and  sporanges  is  called  a 
Sporophyte.  JMacrosporophytes,  Macrosporophylls  and  Macrospor- 
anges  are  those  producing  only  macrospores  or  female  spores.  Micro- 
sporophytes,  Microsporophylls,  and  INIicrosporanges  are  those  producing 
only  microspores  or  male  spores. 

Dioecious,  Monoecious  and  Polygamous  Flowers. — When,  as  in  this 
case,  the  macrospores  are  produced  })y  one  plant  and  the  microspores 
by  another,  the  plant  is  dioecious.  If  in  addition  each  plant  produced 
some  perfect  flowers  it  would  be  Dioeciously  Polygamous.  If,  as  in  the 
Alder  (Fig.  15)  pistillate  flowers  (a)  and  staminate  flowers  (b),  or  other- 


PARTS  OF   THE  PISTIL  31 

wise  stated,  spores  of  both  sexes,  are  produced  by  tlie  same  plant,  it 
is  Monoecious.  If,  in  adition,  the  phmt  bear  some  perfect  flowers  it  is 
Monoeciously  Polviianious. 

Hermaphrodite  and  Perfect  Flowers, — When,  as  illustrated  in  Fig.  17, 
the  flower  possesses  both  gynaecium  and  androecium,  it  is  Hermaphro- 
dite, indicated  by  the  symbol  9.  Hermaphrodite  flowers  are  not 
always  perfect,  as  one  of  the  organs,  while  perfect  in  form,  may  be 
functionless;  whereas,  in  order  to  be  perfect,  both  parts  mnst  be  present 
and  functionally  active. 

Degrees  of  Imperfection. — Imperfect  flowers  present  all  intermediate 
grades  between  that  last  mentioned  and  that  in  which  there  remains 
no  trace  of  the  lost  part,  or  in  which  it  has  even  been  transformed  into 
an  organ  of  a  different  kind. 

Parts  of  the  Stamen. — The  stem-like  portion  (Fig.  12,  c)  regarded  as 
corresponding  to  the  petiole  of  the  sporophyll,  is  the  Filament.  The  por- 
tion containing  the  spores  or  pollen  is  the  Anther  (d).  The  two  halves  of 
the  anther,  each  corresponding  to  a  half  of  the  lamina  of  the  sporophyll, 
are  the  Thecae  (Fig.  14,  a).  At  an  earlier  stage  each  theca  is  subdivided 
into  two  Locelli  (Fig.  14,  c),  and  in  many  plants  this  condition  persists 
to  maturity  (Fig.  138).  The  portion  connecting  the  thecae  with  one 
another  and  with  the  filament  is  the  Connective  (b).  Our  detailed 
study  of  the  stamen,  as  of  the  pistil,  may  here  be  anticipated  by  the 
statement  that  any  or  all  of  their  parts  may  in  different  flowers  be  found 
modified  in  an  extreme  degree  by  reduction,  exaggeration,  or  special 
form  of  growth,  and  may  bear  appendages  in  great  variety,  their  true 
nature,  or  even  their  identity,  in  many  cases  being  thus  masked.  Often 
an  a])i)endage  aj)parently  consisting  of  a  modified  stipule  exists. 

Parts  of  the  Pistil. — The  stem-like  base  (Fig.  9,  a),  not  present  on 
most  pistils,  is  the  Stipe  or  Thecaphore.  It  represents  the  united 
petioles  of  the  sporophylls.  The  body  of  the  pistil  represents  either  a 
single  sporophyll  having  its  edges  brought  together  and  united,  with 
the  upper  leaf-surfaces  inside  of  the  cavity  (Figs.  219  and  220),  or,  as 
in  this  case,  more  than  one  sporophyll,  the  edges  of  one  meeting  those 
of  the  other  in  the  same  manner  (Fig.  27,  e)  or  in  many  cases  in  a^ifl'er- 
ent  manner.  The  edges,  after  meeting  along  the  hollow  portion,  project 
inward  more  or  less,  while  along  the  tip,  for  a  greater  or  less  distance, 
they  may  be  everted,  as  seen  in  Fig.  17,  b.  A  s])oroi)hyll  of  a  pistil  is  a 
Carpel,  and  we  see  that  a  pistil  may  consist  of  one  or  more  carpels. 

The  seed-rudiments  which  ])r()duce  and  contain  the  macrospores 
are  the  0^•ules  (Fig.  10,  b).    The  outgrowth  from  the  inner  wall  of  the 


32      ANTHOLOGY:   THE  GENERAL  NATURE  OF    THE  FLOWER 

ovary  iipon  which  the  ovules  develop  is  the  Placenta  (Fig.  10,  a).  The 
hollow  portion  of  the  pistil,  containing  the  placentae  and  ovules  is  the 
Ovary  (Fig.  9,  b).  The  divisions  of  the  ovarian  cavity,  which  sometimes 
exist,  are  called  Cells  (Fig.  221,  etc.),  and  the  partitions  which  separate 
them  are  called  Septa  or  Cell  walls.  A  point  upon  a  pistil  (Fig.  9,  d) 
which  lacks  its  epidermis  and  permits  entrance  into  the  ovary  of  the 
pollen-product  is  a  Stigma.  (See  also  Figs.  191,  etc.)  A  portion  con- 
necting the  stigma  to  the  ovary,  narrower  than  the  latter  and  usually 
not  hollow,  is  the  Style  (Fig.  9,  c). 

The  leafy  nature  of  the  Carpel  and  its  products  is  well  illustrated 
by  Fig.  19,  which  represents  a  reverted  state  of  the  pistil. 

The  Essential  Organs. — Since  the  androecium  and  gynaecium  are 
capable  of  producing  seeds  without  the  necessity  for  other  floral  parts 
they  are  commonly  known  as  the  Essential  organs,  others  as  the  Non- 
essential organs. 

Protection  Needed  by  the  Essential  Organs. — The  danger  of  accident, 
as  the  result  of  blows,  punctures,  erosion,  or  even  changes  of  tempera- 
ture, to  the  complex  mechanism  and  delicate  structure  of  the  essential 
organs,  and  the  resulting  necessity  for  their  protection,  is  obvious.  In 
the  case  under  consideration  the  flowers  are  so  closely  crowded  upon 
their  supporting  branch  that  their  leaf-scales  (which  are  not  parts  of 
the  flowers,  but  grow  out  underneath  them,  from  the  nodes)  afford 
the  necessary  protection.  But  commonly  this  is  not  the  case,  and  each 
flower  must  provide  and  possess  its  own  protecting  organs.  It  must  be 
borne  in  mind,  however,  that  protection  is  usually  the  least  important 
office  which  such  organs  fulfil. 

The  Calyx. — A  series,  or  apparent  or  real  circle,  of  such  modified 
leaves,  underneath  or  surrounding  the  androecium,  is  displayed  in  the 
flower  of  Pulsatilla  (Fig.  16,  a)  and  constitutes  its  Calyx,  frequently 
indicated  by  the  symbol  K,  the  several  leaves  being  called  either  Sepals 
or  Calyx-Lobes,  in  accordance  with  conditions  to  be  considered  hereafter. 

The  Corolla. — Commonly,  there  is  a  second  series  or  circle  betAveen  the 
calyx  and  androecium,  as  in  the  buttercup  (Fig.  17,  a),  and  this  is  called 
the  Corolla,  frequently  indicated  by  the  symbol  C,  its  several  leaves. 
Petals  or  Corolla-lobes,  according  to  their  condition.  Rare  cases 
occur  in  which,  although  but  a  single  circle  is  present,  it  is  regarded  as 
a  corolla. 

Sinuses. — The  space  between  two  adjacent  petals  or  corolla-lobes — and 
the  same  is  true  of  a  similar  space  between  any  two  organs  or  divisions 
standing  side  by  side — is  called  the  Sinus. 


THE   TORUS 


33 


Petals  and  Sepals. — Occasionally  the  petals  will  he  mimeroiis,  forming 
more  than  one  circle.  A  petal  or  sepal  is  normally  not  composed  of 
distinct  parts,  unless  it  be  by  a  narrowed  insertion,  called  the  Unguis 
or  Claw,  which  is  frequently  present  (Fig.  18,  a),  the  broad  part  being 
called  the  Lamina,  Blade,  or  Limb.  It  is  then  said  to  be  r'nguicu- 
late.  Usually  the  form  of  sepals  and  petals  is  more  obviously  leaf-like 
than  that  of  the  stames  and  carpels,  and  frequently  in  color  and  texture, 
particularly  of  the  sepals,  they  are  strongly  foliaceous.  The  calyx  and 
corolla  may,  however,  possess  any  color  or  texture  and  they  may  be 
similar  or  dissimilar,  usually  the  latter,  in  this  feature.  The  petals,  as 
w'vW  as  the  sepals,  may  even  difl'er  among  themselves  in  color  and  texture. 


Fig.  16.  Flower  of  PulsaliHa,  subtended  by  epicalyx,  with  calyx  of  6  sepals;  a,  torus;  6  and  c,  rudi- 
mentary or  aborted  petals  17.  Flower  of  Adonis,  a,  petal;  &,  pistil;  c,  stamen.  18.  Unguiculate 
petal  of  Diaiithus.    a,  unguis  or  claw.     19.  Flower  with  its  carpel  partly  reverted  to  the  leaf-form. 


The  Perigone. — The  calyx,  or  the  calyx  and  corolla  together  when  both 
exist,  constitute  the  Perigone,  less  aptly  called  the  Perianth  or  Floyal 
I'nvelopes.  A  flower  possessing  both  calyx  and  corolla  is  called 
Dichlamydeous;  one  with  calyx  only,  Monochlamydeous,  indicated 
by  Co,  and  one  with  neither,  Achlamydeous  or  Naked,  indicated  by 
Ko-Co.     Those  which  have  no  corolla  are  called  xA.petalous. 

The  Complete  Flower. — A  flower  possessing  calyx,  corolla,  androecium, 
and  gynacciiini  is  called  Complete. 

The  Neutral  Flower.— Some  i)lants  habitually  i)roduce  a  portion  of 
their  flowers  without  essential  organs  (Fig.  2(18,  a).  Such  flowers  are 
called  Neutral. 

The  Torus. — It  must  ever  be  borne  in  mind  that  all  these  parts  are 
constructed  of  the  modified  leaves  of  the  floral  branch.  The  latter  is 
called  the  Torus  or  Thalamus,  or,  less  desirably,  the  Ileceptacle.  The 
torus  may,  therefore,  be  defined  as  the  reduced  branch  which  gives  origin 
to  the  jxirts  of  the  /lower  {a,  in  Figs.  10,  23,  and  24). 
3 


34      ANTHOLOGY:   THE  GENERAL  NATURE  OF   THE  FLOWER 

Relation  of  the  Flower  and  its  Parts  to  the  Branch  and  its  Leaves. — The 
relation  of  these  parts  to  their  branch  may  be  displayed  by  comparing 
the  leafy  stem  of  a  lily  Mith  the  dissection  of  a  lily  flower  (Fig.  20). 


Fig.  20.  Diagram  showing  homology  between  leafy  stem  and  flower  of  lily,  the  lowest  whorl  of  former 
corresponding  to  the  calyx  of  latter,  the  second  to  the  corolla,  the  third  and  fourth  to  the  two  sets 
of  stamens,  the  uppermost  to  the  carpels,  the  torus  to  the  branch. 

The  Epicalyx. — ^What  appears  to  be  a  double  calyx,  or  one  calyx 
outside  of  another,  is  frequently  seen.    This  appearance  is  sometimes 


Fig.  21.  lAndoiCallirrhoe.  a,  epicalyx;  6,  calyx;  c,  corolla.  22.  The  same  expanded.  23.  Apetalous 
flower  of  Hepatica.  a,  torus;  6,  calyx.  24.  The  same,  calyx  removed,  o,  the  torus  showing  the  epi- 
calyx as  distant. 

due  to  the  actual  manifestation  of  two  circles,  as  in  the  mustard;  at 
others  to  appendaging  (see  Fig.  36),  but  usually  to  a  circle  of  modified 


THE  EPICALYX  35 

foliage  leaves  standing  close  to  the  torus  (Figs.  21  and  22,  a),  and 
known  as  the  Epicalyx.  When,  as  in  this  case,  the  flower  has  in  addition 
a  calyx  and  corolla  the  real  nature  of  the  epicalyx  is  readily  understood. 
But  when  (Fig.  23)  there  is  no  corolla,  the  calyx  (h)  being  colored  like 
one,  the  epicalyx  may  easily  be  mistaken  for  a  calyx.  In  this  instance, 
however,  it  may  be  seen  by  turning  back  the  epicalyx  or  removing  the 
calyx  (Pig.  24)  that  the  point  of  insertion  of  the  former  is  upon  the 
stem  below  the  torus  («),  so  that  it  can  be  no  i)art  of  the  flower 
proper.  The  divisions  of  the  epicalyx  are  called  Bracts,  though  the 
term  is  not  restricted  to  this  use,  as  will  be  seen  farther  on. 


CHATTER    III 

LAWS   OF   FLORAL   STRUCTURE 

Meaning  of  the  Term. — When  we  speak  of  a  natural  law  as  governing 
a  certain  natural  object,  we  refer  merely  to  some  observed  mode  or 
manner  of  the  existence  of  that  object.  Thus  it  is  a  law  that  water 
flows  downward,  because  that  has  been  observed  to  be  one  of  the 
peculiarities  of  this  substance.  Similarly,  warm  air  rises,  wood  burns 
when  fire  is  applied  to  it,  and  the  sepals  and  petals  of  a  flower  possess 
a  similar  form  to  that  of  the  leaves  of  the  plant  on  which  they  grow 
and  of  which  leaves  they  are  homologues.  Nevertheless,  water  will 
sometimes  run  up  hill  because  it  is  forced  up,  warm  air  sometimes  does 
not  rise  because  it  is  confined,  wood  will  not  burn  because  it  is  wet  or 
otherwise  fireproof,  and  the  sepals  and  petals  will  not  conform  with  the 
leaves  because  some  plants  have  no  leaves,  or  because  the  influence  of 
some  other  law,  known  or  unknown  to  us,  has  interfered  with  the  action 
of  the  one  stated. 

Under  the  natural  and  unobstructed  influence  of  the  morphological 
development  of  the  flower  from  a  branch  and  of  its  parts  from  the  leaves 
of  that  branch,  the  flower  and  its  parts  would  possess  certain  definite 
and  typical  characters.  In  the  process  of  such  development,  however, 
there  is  a  constant  tendency  toward  variation  from  the  typical  state, 
the  extent  and  direction  of  which  variation  are  determined  by  the 
external  conditions  and  forces  to  which  the  living  plant  is  subject,  so 
that,  as  a  rule,  flowers  differ  greatly  from  that  typical  state.  A  careful 
study  of  all  flowers  will  nevertheless  show  that  their  general  plan  of 
structure  is  in  accordance  with  these  laws,  with  more  or  less  variation 
in  the  details. 

Modification  of  the  Typical  Flower. — We  shall  here  consider  the  laws 
of  floral  structm-e  in  relation  to  the  following  characters:  The  relative 
number  and  position  of  parts  of  different  kinds  or  of  different  series,  as 
those  of  the  calyx  compared  with  those  of  the  corolla,  or  of  the  andro- 
ecium  compared  with  those  of  the  gynaecium;  the  separation  of  each 
part  from  every  other,  both  of  the  same  and  of  different  kinds  or  series; 
a  similarity  in  form  and  size  of  the  parts  composing  any  one  series; 


SYMMETRICAL  FLOWERS 


37 


the  characteristic  form  and  function  of  all  the  parts  of  one  kind.  P'or 
the  identification  of  the  parts  of  a  typical  flower,  the  few  illustratiojis  and 
definitions  already  given  will  prove  ample,  but  such  flowers  are  very 
rare.  The  great  majority  of  them  de\'iate  from  the  tj'pe  in  one  or  more 
directions  to  such  a  degree  and  in  such  a  variety  as  to  very  frequently 
create  difficulty  in  identifying  or  circumscribing  the  several  parts.  To 
fit  the  student  for  properly  meeting  the  difficulties  which  so  arise,  as 
well  as  for  understanding  botanical  terminology,  it  is  necessary  to 
specify  and  explain  the  principal  forms  of  variation  and  to  establish  such 
a  classification  of  them  as  their  varied  nature  will  permit. 

Law  1:  Symmetrical  Flowers. — The  number  of  parts  of  each  kind  or 
series  is  the  same  as  of  each  other,  or  they  have  a  common  multiple.  The 
term  Isomerous  is  used  to  indicate  that  the  same  number  of  parts  enter 
into  the  formation  of  the  two  or  more  circles  to  which  the  term  is  appHed. 
In  the  case  of  the  gynaecium,  it  is  the  carpels  which  are  counted  as 
parts  of  the  circle  or  series,  whether  developed  each  as  a  se])arate  pistil, 
or  all  united  into  one.  The  number  of  stamens  is  normally  equal  to 
that  of  the  sepals  and  petals  com})inctl,  that  is,  they  form  two  circles. 
If  the  flower  is  typical,  the  number  of  stamens  will  thus  be  just  twice  as 
great  as  that  of  the  parts  of  any  other  kind.  A  flower  constructed  in 
accordance  with  this  law  is  called  Svmmetrical. 


Fig.  25.  Ai>i)ar('iitl.v  nioiioniorou.s  flowor  of  I/ippuris.  a,  raly.\;  c,  stamen;  <i,  pistil.  20.  Longitu- 
dinal section  of  same.  27.  Dinierou.s  flower  of  liicuntUa.  a,  sepals;  b,  original  petals;  6',  petal-like 
bodies  developed  from  one  pair  of  stamens;  c,  the  other  pair  of  stamens,  each  divided  into  three;  d, 
pistil;  e,  eros.s-seetion  of  ovary,  showing  two  placentae.  28.  Trimcrous  flower  of  VercUrutn.  29. 
Tetramerous  flower  of  Ocnulhcra.     30.   Pentamerous  flower  of  Grrauium. 


Terms  Indicafin;/  Niuncrical  Synivicfri/.— Thus,  the  flower  oi  Ilipjniris 
(Figs.  25  and  2G)  has  an  entire  calyx,  apparently  of  one  sepal,  no  corolla, 


38  LAWS  OF  FLORAL  STRUCTURE 

one  stamen,  and  one  carpel,  and  is,  in  its  present  state,  Monomerous 
or  One-merous.  The  symmetrica]  flower  of  Bicuculla  (Fig.  27)  possesses 
two  sepals  (a),  four  petals  (6  and  b'),  six  stamens  (c),  and  a  two-carpelled 
pistil  {d  and  e),  and  is  Dimerous  or  Two-merous.  That  of  the  Veratrnm 
(Fig.  28)  is  similarly  based  on  the  plan  of  three,  and  is  Trimerous  or 
Three-merous.  Oenothera  (Fig.  29)  is  Tetramerous  or  Four-merous, 
and  Geranium  (Fig.  30)  is  Pentamerous  or  Five-merous.  Fig.  43  displays 
the  plan  of  such  a  flower  in  cross-section  and  admirably  illustrates  our 
second  law  also. 

Suppression  and  Duplicatio7i. — Suppression  results  in  the  posses- 
sion of  less  parts  of  one  kind  than  are  possessed  by  the  typical  flower, 
while  Duplication  results  in  the  possession  of  more.  From  what  follows 
it  will  be  seen  that  neither  suppression  nor  duplication  necessarily  inter- 
feres with  the  numerical  plan,  although  they  frequently  do  so. 

In  the  monochlamydeous  flower  of  Pulsatilla  (Fig.  16)  suppression 
of  the  entire  circle  of  petals  has  occurred,  although  vestiges  of  them 
remain.  In  the  staminate  and  pistillate  flowers  of  the  willow,  all 
organs  except  a  single  series  are  suppressed.  In  the  Claytonia  (Fig.  45) 
one  complete  stamen-circle  has  been  suppressed. 

In  all  these  cases  the  remaining  parts  accord  with  the  numerical  plan 
and  the  flowers  are  still  symmetrical.  Suppression  which  thus  results 
is  called  Regular  Suppression. 

Irregular  Suppression. — This  is  displayed  in  the  calyx  of  Claytonia, 
with  three  of  its  five  sepals  wanting,  in  the  androecium  of  the  4-  or 
5-merous  flower  of  Horse-chestnut,  which  usually  wants  1  to  3  of  the 
requisite  number  of  stamens,  and  in  the  gynaecium  of  the  4-merous 
flower  of  the  olive  (Figs. 31  and  32),  which  has  but  two  carpels  remaining. 
In  this  flower,  both  forms  of  suppression  appear  to  have  occurred,  for 
but  2  of  its  8  original  stamens  remain.  To  irregular  suppression  the 
term  Abortion  has  been  applied,  while  by  others  this  is  restricted  to 
suppression  in  which  a  vestige  of  the  lost  organ  remains,  as  in  case  of  the 
petals  of  Pidsatilla,  and  one  set  of  stamens  in  Fig.  38,  a. 

Regular  Duplication. — Duplication,  like  suppression,  presents  a 
regular  and  an  irregular  form.  Kegular  duplication  is  seen  in  the 
5-merous  flower  of  the  strawberry  (Fig.  36),  with  its  10  sepals;  the 
3-merous  flowers  of  Magnolia  (Fig.  35),  with  6  to  9  petals,  and  Meni- 
spermum,  with  12  to  24  stamens,  and  in  the  5-merous  flower  of  Maha, 
which  frequently  has  10  carpels. 

Chorisis  and  Syngenesis. — The  development  into  two  or  more  sepa- 
rate parts  of  an  organ  originally  entire  is  called  Chorisis.  This  is  exhibited 


SYMMETRICAL  FLOWERS 


3d 


^-AX 


W 


/  /  / 


in  the  androecium  of  the  mustard,  where  the  multipHcation  of  two  of 
the  stamens,  each  into  two,  has  occurred.  The  development  in  a  united 
condition  of  two  or  more  organs  originally 
separate  is  called  Syngenesis.  This  is  exhibited 
in  the  two  carpels  of  the  mustard,  which  are 
united  to  form  a  single  pistil. 

The  nature  of  the  process  is  illustrated  by 
the  accompanying  diagram  (Fig.  30  A).  Let 
a  represent  a  mass  of  elementary  tissue  which 
is  normally  to  develop  into  a  stamen.  If  it 
develop  by  a  uniform  growth  throughout  the 
mass,  it  will  become  a  single  stamen,  d.  If, 
upon  the  other  hand,  it  grow  separately  at  the  points  h,  c,  and  d,  it 
must  result  in  the  production  of  three  separate  bodies,  each  of  which 


^^ 


Fig.  30  A.     Diagram  illustrating 

the  process  of  chorisis. 


Figs.  31  and  32.  Tetramerous  flower  of  olive,  6  of  its  stamens  and  2  of  its  carpels  suppressed.  31. 
Same  in  longitudinal  section.  33.  Androecium  of  mustard,  showing  a  stamen  developed  as  two, 
through  chorisis.  34.  Flower  of  Tilia,  showing  each  stamen  developed  into  a  cluster  and  a  petal 
through  chorisis.  37  shows  such  a  cluster  detached.  35.  Diagram  of  transverse  section  of  Magnolia, 
showing  duplication  through  metamorphosis.  3G.  Flower  of  strawberry,  the  calyx-appendages  simu- 
lating an  cpicalyx.  38.  Androecium  of  Fsorospermum,  the  stamens  of  one  set  undergoing  chorisis, 
those  of  the  other  aborted  into  gland-like  bodies.  39.  Flower  of  Stellaria,  the  corolla  apparently 
double.  40.  A  petal  of  the  same,  bi6d  by  chorisis.  41.  Flower  of  rarojacHW,  the  calyx  having  under- 
gone chorisis. 

may  become  a  perfect  stamen,  as  represented  by  the  dotted  lines.    The 
process  thus  results  in  branching. 


40  LAWS  OF  FLORAL  STRUCTURE 

The  important  point  for  the  student  to  note  is  that  while  we  should 
thus  have  three  stamens  as  to  form  and  function,  we  should  have  but 
one  as  to  the  numerical  plan  of  the  flower,  for  all  have  developed  from 
the  point  belonging  to  one,  and  from  the  elementary  tissues  of  one,  and 
all  represent  but  one  leaf-homologue.  Sometimes  the  total  number  of 
stamens  (or  other  parts)  will  thus  be  multiplied,  each  element  under- 
going the  same  change,  while  at  others  only  one  or  two  in  the  circle  will 
be  thus  modified.  The  latter  would  result  in  irregular  duplication.  In 
studying  the  law  of  position  of  parts,  we  must  note  the  great  difference 
between  duplication  occurring  in  this  way  and  that  from  the  develop- 
ment of  a  new  circle  independently  of  any  process  of  chorisis.  This 
peculiarity  of  position  in  chorisis  is  well  illustrated  by  the  flower  of 
Tilia  (Fig.  34),  where  three  groups  or  fascicles  of  stamens  can  be  seen, 
each  produced  from  one,  and  in  that  of  Psorospermum  (Fig.  .38)  where 
there  are  five,  the  separation  being  here  confined  to  the  upper  portion. 
In  this  case,  remains  of  a  suppressed  circle  of  stamens  are  present  in  the 
form  of  gland-like  bodies  (a).  Chorisis  is  well  displayed  in  the  calyx  of 
a  floret  of  the  Dandelion  (Fig.  41),  whose  sepals  have  become  divided 
into  numerous  bristle-like  portions,  and  in  the  corolla  of  the  SteUaria 
(Fig.  39),  each  of  whose  petals  (Fig.  40)  has  become  divided  into  two. 

Production  by  Chorisis  of  a  Part  of  a  Different  Kind. — Chorisis  some- 
times produces  an  organ  of  a  difterent  kind  from  the  original,  as  in  the 
case  of  the  original  stamens  of  the  Tilia,  where  each,  besides  dividing 
into  about  7  stamens,  has  at  the  same  time  yielded  one  or  more  little 
petals  (Fig.  37,  a)  standing  in  front  of  the  stamen  group. 

Median  and  Lateral  Chorisis. — Chorisis  is  Median  in  the  case  of  the 
last-mentioned  petals,  which  stand  in  front  of  the  organ  out  of  which 
they  were  formed.  Lateral  in  the  case  of  the  stamens,  which  stand 
beside  the  organ  out  of  which  they  were  formed. 

An  Indefinite  Number  of  Parts. — When  the  number  of  organs  of  one 
kind,  as  of  petals,  as  in  the  rose  (Fig.  59),  or  of  stamens  (Fig.  GO), 
exceeds  twenty,  it  is  commonly  spoken  of  as  Indefinite,  indicated  by 
the  symbol  go  ,  although  in  most  cases  it  falls  within  certain  definite 
upper  and  lower  limits  which  are  of  diagnostic  value. 

Indication  of  the  Numerical  Plan  by  Diagram. — The  numerical  plan 
and  deviations  therefrom  are  often  indicated  pictorially  by  diagrams 
like  that  shown  in  Fig.  43.  When  dots  are  introduced,  as  in  this  dia- 
gram, they  indicate  the  position  of  organs  which  should  be  present  in 
accordance  with  the  floral  type,  but  which  have  in  that  case  suffered 
suppression.     A  diagram  thus  marked  is  called  Theoretical,  while  if 


ALTERNATION  OF  POSITION 


41 


the  (lots  arc  omitted  it  is  called  Empirical.  Frequently,  also,  a  dot  is 
placed  above  the  dia<,n-am  to  indicate  the  jiosition  of  the  plant-stem  on 
which  the  flower  is  borne,  this  being  the  Su])erior  or  Posterior  side  of 
the  flower,  while  underneath  it  is  often  indicated  the  leaf  or  })ract  in  the 
axil  of  which  it  is  situated,  this  being  the  Inferior  or  Anterior  side  of  the 
flower, 

^S  o 


Fig.  43.  Diagram  of  transverse  section  of  Geranium,  showing  the  alternation  of  parts.  44.  Vertical 
view  of  Illipe,  one  set  of  stamens  alternating  with,  the  other  opposite  to,  the  corolla-lobes,  and  several 
of  the  stamens  aborted.  45.  Flower  of  Ctaytonia  with  outer  set  of  stamens  suppressed.  46.  One  of 
the  remaining  stamens  anteposod  to  petal.  47.  Typical  flower  of  Sedum.  48.  Slightly  irregular 
coToWa.  of  Pelargonium. 

Iiultvditon    (if    ilic     Xiinicricdl    Plan    hi/    For/// ///a.- -The    inanner   of 
indicating  by  formulae  the  numl)er  of  parts  in  calyx,  corolla,  androecium, 
or  gynaecium  has  already  been  indicated.    It  will  now  be  seen  that  by 
a  combination  of  these  expressions,  the  entire  plan  of  the  flower  can 
be  indicated  by  a  single  formula.    K3,  C3,  A3  +  3,  G-  indicates  3  sepals, 
3  petals,  2  circles  of  3  stamens  each,  and  2  carpels.    K3,  C3,  A^  +  0,  G^, 
would  indicate  that  the  second  circle  of  stamens  had  suffered  suppres- 
sion, but  each  of  the  first  circle  had  divided  into  three.    In  a  diagram, 
the  positions  of  the  suppres.sed    stamens  would  be  indicated      ^  ^-^ 
bv  dots,  while  the  doubled  set  remaining  would  be  indicated  in    /.    .  o 
pairs,  thus:    The  letter  n,  in  j)lacc  of  a  figure,  as  in  the  follow- 
ing formula,  Ko,  Go  Ao  +  n,  G'',  indicates  that  the  number  of  parts  of 
that  kind  (in  this  case  the  stamens  of  the  second  circle)  is  not  constant. 

Law  2 :  Alternation  of  Position.     The  parts  of  each  circle  alternate  in 
position  with  those  of  the  adjacent  circles.     In  other  words,  each  i)art  of 


42 


LAWS  OF  FLORAL  STRUCTURE 


the  flower  stands  opposite  a  sinus  of  the  adjacent  outer  and  inner  circles. 
Thus,  in  Fig.  44,  the  stamens  of  the  circle  nearest  the  corolla-lobes 
alternate  with  the  latter,  while  those  of  the  next  circle  alternate  with 
the  former  and  are  consequently  opposite  to  the  corolla-lobes.  In  Fig. 
43  the  same  relation  can  be  observed  between  the  other  circles.  It  is 
thus  clear  that  the  parts  of  two  alternating  circles,  as  of  the  first  and 
third,  or  the  second  and  fourth,  must  stand  opposite  each  other,  or  in 
the  same  radial  line. 

Anteposition  Resulting  from  Suppressioji. — It  is  also  clear  that  if 
two  circles  shall  be  brought  into  juxtaposition  by  the  suppression  of 
an  intervening  circle,  their  parts  will  naturally  stand  opposed  and  thus 
appear  to  invalidate  our  second  law,  as  in  the  case  of  the  stamens  and 


"Vi>^. 


J7 

Figs.  49  to  53.     Figures  illustrating  torsion. 


petals  of  Claytonia  (Figs.  45  and  40),  where  the  stamen-circle  originally 
standing  between  the  other  one  and  the  corolla  has  been  suppressed. 
Organs  thus  placed,  the  one  directly  in  front  of  the  other,  are  called 
anteposed. 

Note  should  also  be  taken  of  the  fact,  already  pointed  out,  that  the 
cluster  of  organs  produced  by  chorisis  corresponds  in  position  with  the 
single  part  by  the  modification  of  which  it  was  produced. 

Position  Sometimes  Obscured. — In  examining  the  position  of  parts 
great  care  should  be  taken  by  the  student  to  see  the  actual  point  of 
insertion,  as  the  free  portion  of  an  organ  frequently  deviates  from  the 
line  of  its  true  position  and  leads  to  error. 

Torsion. — One  such  condition  which  can  easily  lead  to  error  is 
Torsion,  or  twisting.     This  relates  to  a  permanent  condition  of  the 


REGULARITY  43 

mature  organ  and  not  a  temporary  eml)ryonic  state  such  as  the  twisting 
of  the  coroUa  in  the  bud.  Torsion  of  the  base  of  the  coroHa  is  shown  in 
Fig.  49,  of  the  stamens  in  Fig.  50,  of  the  anther  in  Fig.  51,  of  the  style 
in  Fig.  52,  and  of  the  fruit  in  Fig.  53.  Torsion  also  frequently  affects 
other  parts  of  the  plant,  especially  the  stems  of  flOwer  and  leaf. 

The  treatment  of  the  subject  of  position  here  presented  is  necessarily 
superficial  and  incomplete,  owing  to  our  failure  to  have  considered 
already  the  subject  of  leaf-arrangement.  There  is  a  direct  correlation 
between  the  arrangement  of  foliage-leaves  and  the  parts  of  the  flower. 
As  the  arrangement  of  the  former  is  sometimes  by  circles  or  whorls  and 
sometimes  by  spirals,  it  follows  that  some  flowers  may  be  arranged  on 
the  former  plan  (Fig.  20),  some  (at  least  in  part)  upon  the  latter,  and 
such  we  actually  find  to  be  the  case.  There  is  no  one  of  the  floral  series 
but  what  at  times  exhibits  in  its  parts  (in  most  cases  when  they  are 
numerous)  a  well-marked  spiral  arrangement.  Such  are  denominated 
Acyclic,  while  those  having  their  parts  in  true  whorls  or  circles  are 
called  Cyclic. 

Flowers  Normally  Possessing  hut  One  Stamen-circle. — It  should  be 
noted  that  the  very  frequent  occurrence  of  flowers  possessing  but  one 
stamen-circle,  and  this  alternating  with  both  carpels  and  petals,  has 
led  to  the  belief  that  in  some  plants  but  one  stamen-circle  is  the  rule,  a 
second  calyx-circle  existing  instead  of  the  second  stamen-circle.  Care 
should  be  taken  not  to  confuse  the  idea  of  this  second  calyx-circle  with 
that  of  the  totally  different  epicalyx. 

Law  3:  Regularity. — The  parts  composing  one  circle  agree  in  form  and 
size.  A  How'cr  all  of  whose  circles  obey  this  law  is  liouular.  An  illus- 
tration is  found  in  the  flower  of  Veratnun  (Fig.  28). 

Ir  regular  it  y  and  How  it  May  Result. — Irregularity  may  result  from 
abortion  (Fig.  44),  where  three  of  the  upper  circle  of  stamens  are 
different  from  the  other  five;  from  appendaging  (Fig.  05),  where  one  of 
the  five  petals  bears  a  long  spur;  or  from  mere  variation  in  form  (Fig. 
110)  or  size  (Fig.  48).  Sometimes,  as  in  the  last  case,  the  variation  is 
so  slight  that  the  student  will  be  in  doubt  as  to  its  existence,  while  at 
other  times  an  accidental  variation  in  an  individual  plant  may  suggest 
irregularity  where  it  is  not  a  characteristic.  Very  often  an  irregularity 
so  slight  as  to  be  scarcely  perceptible  in  the  open  flower  may  be  more 
conspicuous  in  the  bud.  In  cases  of  doubt  the  relationship  of  the  plant 
to  others  whose  flowers  are  regular  or  irregular  may  aid  to  a  decision. 

A  tendency  to  antero-posterior  irregularity  in  flowers  would  apjiear 
to  be  generally  characteristic  of  their  higher  development. 


44  LAWS  OF  FLORAL  STRUCTURE 

Law  4. — Each  part  of  a  circle  develops  separate  and  disconnected  from 
all  others  in  that  and  in  other  circles.  As  the  mass  of  tissue  forming 
each  of  the  floral  parts  becomes  isolated  and  projected  from  the  torus, 
its  margins  and  faces  should  develop  completely  separate  from  those 
of  all  adjacent  parts.  The  law  assumes  that  growth  shall  continue  in 
the  isolated  portions,  by  which  process  they  must  continue  separate. 
But  this  form  of  growth  of  the  parts  does  not  always  occur.  Very 
commonly  the  point  of  growth  changes  or  becomes  restricted  to  the 
basal  portion,  where  they  have  not  yet  separated  from  one  another. 
This  projection  from  the  torus  of  an  undivided  or  unseparated  portion, 
and  its  subsequent  growth,  must  clearly  result  in  the  development  of 
a  portion  of  the  flower  consisting  of  more  than  one  floral  part  in  union. 
The  component  parts  are  usually  indicated  by  more  or  less  of  a  separa- 
tion of  their  apical  portions.  This  principle  has  been  already  carefully 
explained  in  connection  with  Fig.  42. 

Connaiion. — There  is  no  other  direction  in  which  deviation  from  the 
type  represented  in  Fig.  47  is  so  frequent  and  variable  as  in  that  just 
described,  nor  in  which  the  results  are  so  far-reaching  or  call  for  so 
extensive  a  classification  and  terminology.  The  deviations  are  of  two 
classes.  When  a  part  is  united  laterally  with  another  part  of  the  same 
circle  the  condition  is  called  Connation,  Cohesion,  Coalescence,  or 
Syngenesis.  When  connation  does  not  exist  the  parts  are  said  to  be 
Distinct  or  Eleutherous.  Connation  will  be  discussed  in  our  detailed 
consideration  of  the  several  floral  parts. 

Adnation  or  Adhesion. — In  the  second  form,  called  Adnation  or  Ad- 
hesion, one  circle  is  more  or  less  united  with  another.  Adhesion  may 
affect  any  two  or  more  circles  of  the  flower,  and  it  may  affect  an  entire 
circle  or  only  one  or  more  of  its  parts.  Thus,  Fig.  54  illustrates  a 
petal  of  the  ^'anilla  adnate  to  the  ganaecium,  while  the  other  petals 
are  free.  It  is  plain  that  when  the  calyx  and  gynaecium  are  adnate,  all 
the  intervening  circles  must  be  included  in  the  condition,  as  in  the 
lower  portion  of  the  colocynth  (Fig.  5(5).  Since  all  the  parts  start 
from  the  torus  at  a,  they  must  be  adnate  to  the  whole  surface  of  the 
ovary  between  the  points  a  and  /;. 

Epigyny. — In  the  last  case,  as  in  all  cases  where  one  or  more  circles 
are  adnate  to  the  gynaecium,  the  free  or  ununited  ends  of  the  parts 
must  lose  the  appearance  of  emanating  from  the  torus  and  must  appear 
to  emanate  from  the  gynaecium.  They  are,  therfore,  said  to  be  Epigy- 
nous.  At  this  ])oint  the  student  should  not  fail  to  impress  himself 
with  an  understanding  of  the  fact  that  in  all  such  cases  the  epigynous 


THE  IIYPANTIIIUM 


45 


organs  really  orifjinate  at  the  torus,  and  that  in  a  cross-seetion  through 
the  adherent  ])()rti()ns  the  niieroseope  will  often  demonstrate  the  tissues 
of  such  a  part  adnate  to  those  of  the  part  from  which  it  appears  to 
emanate.  In  descriptive  i)hrase()logy,  the  term  "Calyx  adherent" 
always  means  "adherent  to  the  ovary,"  or  ejjigynons,  e\en  though  the 


Fig.  5-1.  Adnate  petal  of  Viuiilhi.  Tm.  (iynaiiilnius  slauieiis  i.f  .\,l,iihim,  as  prevalent  in  the  Apo- 
cynaceae.  56.  Flower  of  rolorjnth,  with  inferior  ovary  and  superior  (adherent)  calyx.  57.  Longi- 
tudinal section  through  flower  of  I'Mox,  .showing  stamens  adherent  to  corolla.  58.  The  same  through 
flower  of  cherry,  showing  adhesion  of  all  parts  except  the  pistil.  50.  "Double"  flower  of  rose,  showing 
the  stamens  of  tlio  ".single"  fiower  (60)  transformed  into  ix'lals. 


words  "to  the  ovary"  are  omitted 
condition  is  to  say  "Ovary  inferior 


Another  mode  of  stating  tl;e  same 
r  "  ( 'alyx  su])erior."  It  frc(iuentl\- 
happens  that  the  condition  is  only  partial,  when  the  terms  "Half 
inferior"  and  "Partly  inferior"  are  emi)loyed.  'riure  are  cases  where 
proper  aj)])lication  of  any  of  these  tei-nis  is  doiihtful  and  some  ])fr))h'xity 
is  created. 

The  Ili/ixnilliliini.-  In  many  cases  tlie  toiMis,  wliicli  is  to  he  remem- 
bered as  the  end  of  a  hraiich,  is  hollow  and  has  the  lower  portion  of  the 
flower  inside  of  it  and  adherent  to  the  inner  surface  of  its  cup  (Figs. 


46  LAWS  OF  FLORAL  STRUCTURE 

59  and  60).  In  this  case  the  outer  surface  of  its  cup  may  be  mistaken 
for  that  of  an  adherent  calyx.  The  enclosed  portion  of  the  calyx  really 
is  adherent,  but  it  is  not  visible,  since  it  is  enclosed  and  concealed  by  the 
hollow  torus,  which  is  known  as  a  Hypanthium.  It  is  often  extremely 
difficult  to  distinguish  between  a  simple  adherent  calyx  and  a  hypan- 
thium, and  good  botanists  frequently  disagree  in  particular  cases. 

Perigyny. — The  insertion  of  a  corolla  or  an  androecium  which  is 
adherent  to  a  free  calyx,  as  in  the  cherry  (Fig.  58),  or  of  an  androecium 
adherent  to  a  free  corolla,  as  in  the  Phlox  (Fig.  57),  is  denominated 
Perigynous. 

Hyvogyny. — Organs  which  are  not  in  any  way  adherent  are  denom- 
inated Free,  and  because  their  insertion  is  manifestly  upon  the  torus 
underneath  the  gynaecium,  they  are  said  to  be  Hypogynous  (Fig.  47). 

Gynandry. — With  the  stamens  adnate  to  the  pistil  the  flower  is  said 
to  be  Gynandrous  (Fig.  54).  The  body  thus  formed  of  the  united 
androecium  and  gynaecium  is  technically  known  as  the  Column.  (See 
also  "Stamen^column.")  A  peculiar  form  of  gynandry  is  common 
among  the  relatives  of  the  Apocytmm  (Fig.  55). 

Law  5. — Each  part  preserves  its  own  function  and  a  characteristic  form. 
The  forms  freeing  with  this  law  correspond  in  general  with  those 
which  have  been  indicated  in  our  account  of  the  flower.  Deviations 
from  it  are  caused  by  INIetamorphosis,  Enation,  resulting  in  the  true 
appendaging  of  an  organ,  the  very  similar  process  of  exaggeration  in 
the  growth  of  a  part,  retardation  in  its  growth,  or  its  suppression  or 
abortion.  With  the  exception  of  the  first,  the  results  of  these  processes 
will  be  discussed  under  the  details  of  the  respective  parts. 

Metamorphosis  is  the  simulation  in  form  or  function,  or  both,  of  one 
organ  by  another.  The  rose,  which  normally  has  but  five  petals  (Fig. 
60),  is  seen  under  cultivation  to  consist  of  a  dense  mass  of  them,  in 
many  circles,  becoming  a  so-called  "double"  flower.  An  examination 
of  the  inner  petals  of  such  a  flower  (Fig.  59)  discloses  that  they  are 
successively  smaller  and  more  stamen-like  as  they  stand  nearer  the 
stamens,  indicating  their  origin  through  the  metamorphosis  of  the 
latter,  which  are  fewer  in  proportion  as  the  petals  are  more  numerous. 
In  another  form  of  the  rose,  the  "  Green  Rose,"  the  petals  in  turn  appear 
transformed  into  leaves  or  leaf-like  bodies.  Such  accidental  or  artificial 
deviations  from  the  normal  type  are  called  Monstrosities.  The  sepals 
also  frequently  present  a  leafy  appearance,  sometimes  as  an  abnormality 
but  in  most  species  habitually.  Even  the  stamens  and  carpels  fre- 
quently display  the  latter  abnormality. 


GLANDS 


47 


Retrograde  Metam  or  pilosis. — In  all  of  these  cases  the  change  is  from 
a  more  com])lex  organ,  or  one  of  higher  rank,  to  one  of  a  lower,  and  is 
called  Retrograde  i\retani()r])hosis,  or  Reversion  of  Type. 

Progressive  Metaiitorphosis  also  occnrs.  It  is  seen  in  the  gradual 
transformation  of  bracts,  themselves  transformed  leaves,  into  sepals 
in  the  Barberry  (Fig.  (il),  and  of  sepals  into  petals  and  petals  into 
stamens.  Even  stamens  may  become  metamorphosed  into  carpels 
or  carpels  into  stamens,  one  instance  being  the  flowers  of  the  willow, 
where  organs  have  been  seen  intermediate  in  ai)pearance  between  the 
two. 


62. 

Fig.   61.    Structures   from   flower  of   licrhrris,  interiiiodiate  between  petal  and  stamen.     62.    Same 
from   flower  of  Castalia. 


Teratology. — Cases  of  abnormal  retrograde  metamorphosis  are  very 
common,  and  have  given  rise  to  a  separate  department  of  study  known  as 
Teratology. 

Enation  or  Outgrowth. — Enation  and  the  effects  ])rodnced  by  it  are  well 
illustrated  in  one  of  their  forms  by  the  petals  of  certain  genera  of  the 
Ranunculaceae.  The  retention  of  a  drop  of  nectar  at  the  base  of  the 
petal  of  some  species  of  buttercup  is  effected  by  the  presence  there  of  a 
minute  scale  (Fig.  03),  covering  over  a  slight  depression.  The  nectar 
is  partly  lodged  in  this  pit,  partly  held  between  the  petal  and  the 
scale.  In  the  Coptis  (Fig.  04),  a  closely  related  plant,  the  dej)ression 
is  deepened  into  a  more  obvious  cavity  and  the  .scale  is  dispensed  with, 
while  in  the  Delphinium.  (Fig.  65)  the  cavity  becomes  a  long  tube. 

Glands. — Although  the  detailed  consideration  of  appendages  will 
be  taken  up  in  connection  with  tlie  several  organs  to  which  they  apper- 


48 


LAWS  OF  FLORAL  STRUCTURE 


tain,  we  shall  here  consider  a  special  class  of  them,  called  Glands,  not 
only  of  great  importance  in  diagnosis  and  classification,  but  of  such 
physiological  importance  that  from  that  jxnnt  of  \\e\v  they  constitute 
a  distinct  organ  of  the  flower.  For  the  peculiarities  of  structure  and 
secretory  function  of  glandular  tissue,  works  on  histology  must  be 
consulted.  Here  we  note  that  although  glands  are  sometimes  distributed 
through  the  other  tissues  in  such  a  way  as  to  be  imperceptible  on 
superficial  examination,  their  tissue  is  at  other  times  collected  into  more 
or  less  conspicuous  bodies  of  definite  form  and  position.  The  term 
"Gland"  is  frequently  applied  also  to 
bodies  which  resemble  glands  in  location 
and  form,  but  which  do  not  appear  to  be 
glandular  in  function.  Glands  may  be 
stalked  (Fig.  66,  a),  sessile  (Fig.  67,  a), 
or  depressed  (Fig.  6S,  a,  see  Nectary), 
and  they  may  develop  upon  various  parts 


Fig.  63.  (a)  frontal;  (b)  lateral,  views 
of  base  of  petal  of  buttercup,  showing  a 
scale  which  retain  nectar  in  nectary. 
64.  Petal  of  Coptis,  hollowed  to  form  a 
nectary.  65.  Long  hollow  spur  forming 
nectary  in  flower  of  Delphinium. 


Fig.  66.  Stalked  glands  (a)  on  calyx  of  Dinemandra. 
67.  Sessile  glands  (o).  68.  (a)  Depressed  glands  (nectary) 
on  petal  of  Frasera.  69.  (a)  Basal  gland  prevalent  in 
the  Apocynaceae.  70.  (a)  Glands  at  base  of  stamen  of 
Sassafras. 


of  the  flower  or  plant.  Those  upon  the  outside  of  the  calyx  are  exten- 
sively utilized  in  classification  in  the  family  Mali)ighiaceae,  Avhile  those 
upon  the  inside  are  so  used  in  the  families  Apocynaceae  (Fig.  09,  o)  and 
Gesneriaceae. 

Fig.  6S  is  an  illustration  of  glands  located  upon  the  corolla,  while 
Fig.  70,  a,  illustrates  them  connected  with  the  stamens,  as  seen  in 
Sassafras. 

Glands  upon  filament-like  stalks,  suitably  located,  may  easily  be 
mistaken  for  stamens,    (ilands  may  be  themselves  appendaged. 

As  to  their  origin,  it  may  be  stated  that  glands  frequently  result 


EXAGGERATION  OF  GROWTH  49 

from  metamorpliosis  of  the  remains  of  an  aborted  orj?an.  Thus,  in  the 
staminate  willow-flower  (Fig.  12)  a  small  gland  between  the  bases  of 
the  stamens  is  supposed  to  represent  the  aborted  pistil,  while  similar 
ones  at  the  base  of  the  pistil,  in  the  pistillate  flower  (Fig.  9),  are  supposed 
to  represent  the  aborted  stamens. 

The  misleading  effects  of  su])pression  have  been  observed  in  Ilcpatica 
(Figs.  23  and  24)  in  the  absence  of  the  corolla,  the  metamorphosis  of 
the  calyx  toward  corolla  and  of  the  epicalyx  toward  calyx.  Those  of 
abortion  are  seen  in  the  Pulsatilla  (Fig.  16),  where  the  petals  b  and  c 
are  reduced  to  simulate  filaments. 

Exaggeration  of  Growth  is  well  displayed  in  the  torus  of  the  straw- 
berry and  the  placentae  of  the  watermelon  (Fig.  312),  which  respec- 
tively contribute  the  massive  edible  portions  of  those  fruits. 

The  principles  of  anthology  as  api)Iied  to  the  higher  types  of  plants, 
having  thus  been  followed  into  and  through  the  typical  flower,  and  the 
general  nature  of  the  deviations  therefrom  having  been  outlined,  we 
shall  proceed  to  a  detailed  consideration  of  the  several  parts  of  the 
flower,  with  the  object  of  preparing  us  to  interj)ret  the  multiform 
appearances  which  those  organs  present  in  the  extensive  flora  from 
which  our  drugs  are  deri^'ed. 

That  division  will  not,  however,  close  our  consideration  of  flower 
structure,  as  some  imi)ortant  modifications  will  remain  to  be  discussed 
in  our  chai)ter  on  pollination  and  fertilization. 


CHAPTER    IV 

THE   PERIGONE 

Study  of  the  Perigone.— The  perigone  is  to  be  studied  as  to  the  number 
of  its  circles,  their  color,  texture,  and  surface,  the  number  of  parts 
forming  each,  their  adhesion  or  cohesion,  if  existing,  the  form  and 
divisions,  if  any,  of  each  and  of  its  parts,  appendages,  secretions,  meta- 
morphosis or  other  variations,  arrangement  of  the  parts  in  the  bud, 
movements  or  other  noteworthy  habits,  and  duration. 

Number  of  Parts. — The  normal  condition  of  two  circles,  the  modifica- 
tion of  these  through  abortion,  suppression,  duplication  and  meta- 
morphosis, and  their  agreement  with  the  numerical  plan  of  the  flower 
and  its  modification  through  the  same  influences,  need  no  further 
discussion.  The  number  of  parts  entering  into  either  perigone  circle, 
whether  these  exist  in  a  distinct  or  coherent  state,  is  indicated  by  the 
appropriate  numeral  preceding  the  suffix  "phyllous;"  thus  Monophyl- 
lous,  Diphyllous,  Triphyllous,  and  so  on. 

Color  and  Texture. — The  typical  idea  of  a  calyx  more  or  less  herba- 
ceous and  a  corolla  thin,  delicate,  and  brightly  colored,  is  not  always 
realized.  In  the  Crocus  and  most  related  flowers  the  parts  of  both 
circles  are  similarly  petaloid.  The  petals  of  Garcinia  are  thick  and 
fleshy,  in  Caopia  they  are  leathery,  and  in  Alzatea  hard  and  almost 
woody,  at  least  when  dry.  The  surfaces  of  the  sepals,  particularly  the 
outer,  are  not  commonly  glabrous,  while  those  of  the  petals  are;  but 
even  the  latter  are  often  glandular,  pubescent,  densely  woolly,  or  even 
prickly.  No  shade  of  color  is  denied  to  either  circle  of  the  perigone, 
nor  is  the  color  necessarily  uniform  among  its  parts  or  even  over  the 
surface  of  any  one  part.  The  shade  and  marldngs  are  very  liable  to 
vary  in  different  individuals  of  the  same  species,  so  that  color  is  not 
always  a  good  character  on  which  to  base  a  determination.  In  general, 
the  color  deepens  as  the  altitude  of  the  habitat  increases. 

Form  of  Parts. — The  strictly  typical  state  calls  for  a  general  resem- 
blance between  the  form  of  the  perigone  parts  and  that  of  the  foliage 
leaves  of  the  plant  which  bears  them.  They  sometimes  display  a  keel 
corresponding  to  the  mid-rib  of  the  leaf,  and  as  in  the  leaf,  this  may 


ADHESION 


51 


be  continued  into  a  terminal  ])oint.    They  may  be  concave,  as  in  Thco- 
hroma  (Fig.  71);  the  margin  may  be  toothed  and  the  a})ex  tootlied  or 
fim])riated,  as  in  Siletic  (Fig.  72);  the  toothing  of  the  margin  may  extend 
into  a  ])imiatifid  condition,  as  in  the  calyx 
lobe  of  Rosa  canina  (Fig.  73),  and  that  of 
a  toothed  or  fimbriate  apex  into  the  cleft 
or  divided  state  of  chorisis. 

The  Pappus. — The  peculiarly  di\ided 
calyx  illustrated  in  Fig.  79,  a,  is  denomi- 
nated a  rai)pus,  and  this  term  has  been 
extended  to  all  forms  of  the  calyx  (Figs. 
74  to  S3)  existing  in  that  family  (the 
Com positae)  and  in  some  others.  Fig.  80 
illustrates  the  action  of  median,  as  well  as 
of  lateral  chorisis,  in  the  development  of 
a  double  pappus,  the  outer  circle  being 
much  shorter  and  different  in  kind. 

The  se^•eral  forms  of  perigone  i)arts 
corresj)onding  to  those  of  leaves  (see  leaf-forms)  and  numerous  inter- 
mediate ones  not  illustrated,  should  be  carefully  considered  by  the 
student,  as  they  ha^e  a  most  important  bearing  ui)on  the  forms  of  the 
corolla  produced  by  cohesion,  which  we  shall  shortly  consider. 


FiK.  71.  ConoMVc  petiil  of  Tlicohronut. 
72.  FlowtT  of  .SiVi/K,  the  i)etals  loothod 
at  apex  and  bearing  a  crown  at  junction 
of  limb  with  claw;  also  a  conspicuous 
anthophore  in  base  of  calyx.  73.  Pinna- 
tifid  sepal  of  Jiusa. 


IS.  76.    n. 

Figures  illustrating  forms  of  the  pappus;  Fig.  71.  Pappus  little  changed  from  ordinary  superior 
calyx-limb.  75.  That  of  Tanareium,  reduced  to  a  short  cup.  70.  That  of  Absinlhiuiri,  practically 
obsolete.  77.  That  of  yVycthia,  2  of  the  calyx-teeth  awned.  78.  That  of  Griiidelia,  the  two  remaining 
calyx-teeth  aristiform.  79.  That  of  Aruica,  the  ordinary  setose  form.  SO.  The  double  pappus  of 
£ri(/(To;i,  the  outer  series  very  short.  81.  Plumose  bristle  from  pappus  of  Lasiopoffon.  82.  Scaly  bristle 
from  pappus  of  Eriosphaern.    H',i.  Serrate  bristle  from  pappus  of  Cineraria. 

Adhesion. — Both  adhesion  and  cohesion  are  exceedingly  common  in 
the  case  of  the  })erigoiic.  The  foiiner  has  already  been  pretty  fully 
considered.  \Vry  rarely  is  it  so  coiniilete  that  there  is  not  at  least  a 
])()rtioii   of  the   parts   remaining   free.      Since   the   adherent   ])arts  are 


52 


THE  PERIGONE 


alternating,  adhesion  necessarily  involves  the  ultimate  effect  of  cohesion. 
In  the  case  of  cohesion  extended  very  high,  peculiar  effects,  often 
puzzling  to  the  beginner,  are  produced,  as  in  the  case  of  Oenothera 
(Fig.  29). 

Here  the  calyx,  after  adhering  to  the  entire  surface  of  the  ovary  (e), 
is  continued  upward  in  the  form  of  a  long,  slender  tube  resembling  a 
flower-stem.  Inside  of  this  tube  the  petals  and  stamens  are  adnate, 
and  do  not  become  free  until  they  reach  its  summit. 

Cohesion. — Cohesion,  like  adhesion,  may  be  partial  or  complete.  In 
its  slightest  forms,  with  a  mere  band  of  union  at  the  base,  it  may 
escape  observation,  as  in  the  case  of  the  corolla  of  Lysimachia  (Fig.  84). 
In  such  cases  a  decision  is  best  reached  by  carefully  pulling  away  the 


Fig.  84.  Adnate  corolla  and  androecium  of  Lysimachia,  the  parts  of  each  coherent  at  the  base  only- 
87.  Completely  separating  calyptra  of  Eucalyptus.  88.  Partly  attached  calyptra  of  Mitranthes. 
89.  Corolla  of  Oenothera  escaping  through  a  fissure  in  side  of  calyx.  90.  Corolla  of  Ayenia,  its  petals 
coherent  at  summit  only.  91.  Completely  coherent  petals  of  Ipomoea,  leaving  the  margin  merely 
sinuate. 

corolla.  If  there  is  a  union,  however  slight,  the  corolla  may  thus  be 
removed  as  one  body.  Agglutination  will  occasionally  cause  an  appear- 
ance of  cohesion,  but  upon  applying  the  test  here  specified,  the  parts 
will  be  found  to  separate  readily,  without  the  tearing  of  any  tissue. 

The  Calyptra. — A  peculiar  and  extreme  form  of  cohesion  is  that  in 
which  the  sepals  refuse  to  separate  even  at  the  apex  wdien  the  flower 
expands,  and  the  calyx  is  torn  loose  from  its  basal  attachment,  falling 
entire  as  a  Calyptra,  as  in  the  corolla  of  Eucalyptus  (Fig.  87),  or  remain- 
ing attached  at  one  side  as  in  Mitranthes  (Fig.  88).  A  modification  of 
it  permits  the  remainder  of  the  flower  to  escape  through  a  rent  in  the 
side,  as  sometimes  in  the  case  of  Oenothera  (Fig.  89).  Very  rarel}^ 
cohesion  exists  at  the  apex  only,  a  remarkable  instance  being  the  corolla 
of  Ayenia  (Fig.  90). 


SPECIAL  FORMS  OF  CALYX  AND  COROLLA  53 

Terms  Indicating  Cohesion  or  its  Absence.- — When  tlic  ])ctals  are  dis- 
tinct the  coroUa  is  said  to  he  l^lenther()i)etaloiis  or  Choripetalous.  The 
ol(K'r  hut  less  desirable  term  is  Polypetalous.  When  they  are  coherent, 
the  corolla  is  said  to  be  Gamopetalons  or  Synpetalous,  the  older  and 
less  desirable  term  being  Monopetalons.  Corresponding  terms  lor  the 
calyx  are  Eleiitherosepalous,  Chorisepalous,  or  Polysepalous,  and 
Gamosepalous,  Synsepalous,  or  Monosepalous.  In  the  gamopetalous 
and  gamosepalous  state  the  parts  cease  to  be  designated  petals  and 
sepals,  and  are  known  respectively  as  Corolla-lobes  and  Calyx- 
lobes. 

The  relative  altitude  to  which  the  cohesion  is  carried  is  indicated 
by  special  terms.  When  existing  at  the  base  only,  the  circle  is  said  to 
be  parted  (Fig.  84) ;  when  extending  about  half-way  up,  as  in  Solainim, 
Cleft  (Fig.  92) ;  when  still  farther,  but  yet  leaving  a  considerable  portion 
ununited,  as  in  Spigelia,  Lobed  (Pig.  97),  and  when  having  only  traces 
of  the  parts  ununited,  Toothed  (Fig.  102).  A  peculiar  form  is  that  in 
which  the  position  of  the  parts  is  indicated  by  a  mere  waving  irregular- 
ity of  the  margin,  as  in  the  flower  of  Lpomoea  (Fig.  91),  which  is  then 
said  to  be  Sinuate  or  I 'ndulate.  The  student  must  not  fail  to  discrim- 
inate between  the  entirely  different  senses  in  which  these  terms  are 
here  used,  in  reference  to  the  entire  calyx  and  corolla,  and  as  used 
previously  in  reference  to  the  margin  of  a  single  part  thereof. 

Special  Forms  of  Caljrx  and  Corolla. — We  must  next  consider  certain 
specific  forms  of  the  calyx  and  corolla  as  wholes,  which  are  of  \ery 
great  diagnostic  value.  That  the  form  of  a  gamopetalous  corolla  is 
determined  by  the  form  of  the  ])etals  of  which  it  is  composed  is  readily 
seen  by  comparing  Figs.  IS  and  98.  In  Fig.  18  we  have  a  j)etal  with 
a  long,  slender  claw  and  a  broad  limi).  Several  such  petals  united  by 
their  edges  must  yield  a  corolla  with  a  broad  border  supported  upon  a 
long  tube;  just  sucli  a  form  is  that  represented  by  Fig.  98.  Similar 
results  are  shown  in  Figs.  97  and  99,  and  it  is  not  difficult,  on  examining 
these  figures,  to  imagine  the  exact  form  of  the  component  parts.  In 
Fig.  9;^  we  have  a  union  of  somewhat  broader  petals,  while  those  of  Fig. 
MY.]  were  so  ^■ery  sliort  and  broad  as  to  have  resulted  in  a  saucer-slia])ed 
corolla. 

Although  such  characteristic  forms  are  most  numerous  among  the 
coherent  class,  tiiey  are  not  wanting  among  those  in  which  cohesion 
does  not  exist.  Sometimes  a  non-coherent  corolla  will  necessarily 
assume  such  a  form  through  the  restraint  exercisetl  by  coherent  sepals. 
At  other  times  the  form  is  entirely  independent  of  such  restraint. 


54  THE  PERIGONE 

The  Tube,  Throat,  and  Limb. — In  such  corollas  and  calyces  as  are 
represented  by  Figs.  97  to  99,  the  narrow  portion  is  denominated  the 
Tube  and  the  broad  portion  the  Limb.  When  the  change  from  tube  to 
limb  is  not  abrupt,  there  will  be  an  intermediate  portion,  as  displayed 
at  h  in  Fig.  94,  called  the  Throat.  Less  frequently  this  term  is  ap])licd 
also  to  the  delimiting  circle  between  the  limb  and  the  tube  when  these 
do  meet  abruptly.  Occasionally  distinct  contraction  instead  of  a  dila- 
tation will  be  found  at  the  throat,  as  very  frequently  occurs  in  other 
parts  of  the  tube  (Fig.  100). 

The  Margin. — The  terminal  boundary  line,  including  all  its  extensions 
and  intrusions,  is  called  the  Margin,  The  margin  may  intrude  partly 
or  quite  to  the  tube,  so  that  the  cohesion  may  include  none  or  the  whole, 
or  any  part  of  the  throat,  or  of  the  limb. 

Special  Terms  Indicating  Form. — The  terms  regular  and  irregular 
apply  to  lobes  precisely  as  though  they  were  distinct  sepals  or  petals 
and  to  the  united  portions  as  well  as  to  the  lobes.  Some  of  the  terms 
applicable  to  the  forms  of  the  gamopetalous  corolla  (and,  of  course,  to 
the  gamosepalous  calyx)  refer  to  its  entire  body,  while  others  refer  to 
its  several  parts.  The  former  class,  and  among  them  those  which  are 
regular,  will  be  first  considered. 

The  term  Cylindrical  is  self-explanatory.  If  nearly  cylindrical,  it  is 
called  Cylindraceous.  Such  shapes  are  shown  in  Figs.  29  and  99.  If 
such  a  one  is  manifestly  angled,  as  in  the  calyx  of  MimiiJus  (Fig.  94), 
it  is  Prismatic,  and  the  same  is  true  of  other  tubular  forms.  If  the 
entire  body  flares  regularly  (Fig.  97),  or  if  there  is  such  a  flaring  portion 
upon  a  cylindrical  tube,  it  is  called  Infundibular  or  Funnel-shaped. 
The  less  broadened  infundibular  forms  are  called  Trumpet-shaped,  as 
in  the  honeysuckle.  If  the  flaring  portion  or  limb  is  flat,  or  nearly  so 
upon  a  cylindrical  or  cylindraceous  tube,  it  is  called  Ilypocraterimor- 
phous,  H\^ocrateriform,  or  Salverf-orm,  as  in  the  flower  of  the  coffee 
(Fig.  101).  A  corolla  which  is  bell-sha])ed  is  called  Campanulate 
(Fig.  93).  Of  this  there  are  two  sul)-forms,  the  Open  (Fig.  91)  and  the 
Contracted  (Fig.  95).  The  term  Globular  or  Globose  is  self-explanatory. 
It  may  be  specified,  however,  that  the  mouth  must  be  small  and  with 
no  conspicuous  limb,  or  with  the  limb  turned  back  flat  against  the 
body.  Approaches  to  the  globular  form  are  called  Sub-globular  or 
Globoidal.  Other  related  forms  are  the  Ovoid  or  egg-shaped  and 
oblong.  A  somewhat  globoidal  form,  with  conspicuous  recurved 
margins,  is  Urceolate  or  Urn-shaped  (Fig.  102).  Of  the  broader  or 
more  widely  expanded  forms,  the  campanulate  develops  outward  into 


TERMS   I X  1)1  ( 'A  TI Xd   I RREd ll.A  RI T Y 


55 


tlic  llcinisphcrical  and  the  C'ratcritorin  or  Sau('('r-.slia])ccl,  as  in  the 
Kalmia  (Fig.  103).  When  still  more  flattened  out  it  becomes  Rotate 
or  Wlieel  sha])ed,  as  in  the  SoIa}iiiin  (P^ig.  92). 

A  ganiopetalous  corolla  sometimes  has  a  fissure  on  one  side  extending 
nearly  or  entirely  to  the  base  as  in  the  Lobelia  (Fig.  9G).  When  in 
addition  the  corolla  or  the  split  portion  of  it  loses  its  tubular  form, 
becoming  flattened  out,  it  is  called  Lignlatc  or  Strap-shaped,  as  in  the 
Dandelion  (P^ig.  104). 


Special  Formx  of  I'triyoiie. — Fig.  92.  Rotate  corolla  of  Sola/mm,  with  connivent  anthers.  93. 
Campanulate  corolhi  of  Campanula.  91.  Prismatic  calyx  and  bilabiate,  personate  corolla  of  Mimulus: 
a,  the  tube;  b,  the  throat;  c,  the  lower  lip;  d,  the  palate.  95.  Contracted  campanulate  corolla  of 
Leucolhoe.  96.  Fissured  corolla  of  Lobelia.  97.  Infundibular  corolla  of  Spiorlia.  98.  Hypocrateri- 
form  corolla.  99.  Cylindrical  corolla.  100.  Hypocratcriform  corolla  of  Erhiles  with  portion  of  tube 
constricted.  101.  Hypocratcriform  corolla  of  coffee  flower.  102.  Urceolato  corolla  of  Pemettya. 
103.  Crateriform  corolla  of  Kalmia.     104.   LiKulate  corolla  of  Taraxacum. 


Accuracy  Required  in  the  Use  of  Terms.—  The  applicability  to  the  tube 
and  limb  separately  of  many  of  the  terms  here  applied  to  the  entire 
corolla  is  apparent.  It  should  be  noted,  however,  that  very  detailed 
descriptions  of  these  res])ective  parts,  as  well  as  of  the  throat,  with 
specification  of  any  irregularities  and  marks,  are  often  imperatively 
demanded.  This  is  es])ecially  true  of  the  florets  of  the  Compositae, 
where  such  cliaraetcrs,  although  \'ery  slight,  fr{>(|ueiitly  serve  for  si)ecific 
distinction. 

Special  terms  for  forms  resulting  from  the  possession  of  a])pendages 
will  be  considered  hiter. 

Terms  Indicating  Irregularity. — Terms  indieating  irregularity  will  next 
be  considered,  commencing  with  those  ai)plicable  to  the  entire  body. 

Either  the  base  or  the  mouth  is  ()bli{(ue  when  a  plane  transecting 
it  is  not  at  right  angles  to  the  lloral  axis.     The  body  is  declined  (Fig. 


56 


THE  PERIGONE 


107)  when,  either  with  or  without  any  manifest  curve,  its  axis  is  turned 
from  the  perpendicuhir,  so  that  it  rests  more  or  less  against  one  side  of 
the  cal^-x.  It  may  be  Straight  or  Curved,  and  the  curvature  may  be 
Simple  (Fig.  99)  or  Compound  as  in  the  Sigmoid  calyx  of  Aristolochia 
(Fig.  106).  When  dilated  upon  one  side  only  it  is  Ventricose,  as  in 
some  species  of  Salvia  (Fig.  Ill),  or,  if  the  swelling  is  small  and  prom- 
inent, Gibbous  (Fig.  107,  a).  When  the  swelling  is  carried  downward, 
so  as  to  form  a  sac,  as  in  Cypripediuvi  (Fig.  112,  a)  it  is  called  Saccate. 
When  the  dilation  is  directed  upward,  so  as  to  form  a  hood,  as  in  Aconite 
(Fig.  108,  a),  it  is  called  Cucullate  or  Galeate,  and  when  the  hood  is 


//^  //s 


//£  m 


Fig.  105.  One-lipped  corolla  of  Dinoseris.  106.  Sigmoid-curved  calyx  of  Aristolochia.  107.  Corolla 
of  Achimenes,  the  mouth  oblique,  the  base  declined  and  gibbous.  108.  Galeate  upper  petal  of  Aconite. 
109.  Personate  corolla  of  C/ieZone.  110.  Papilionaceous  corolla  of  La^^2/r«s.  111.  Ringent  and  gibbous 
corolla  of  Salvia.  112.  A  saccate  lower  petal  of  Cyprip^dium.  113.  Auricled  calyx  of  Nicandra. 
114.  Dorsal  spur  on  petal  of  Myrmephytum.     115.  Long-caudate  petals  of  Theobroma. 


compressed  laterally  and  much  enlarged  proportionately  to  the  size  of 
the  body  it  is  called  Cristate.  Most  of  these  terms  are  also  applicable 
to  a  single  lip  of  the  form  next  to  be  considered  or  to  a  petal.  When 
one  or  more  of  the  lobes  of  a  corolla  are  separated  by  a  deeper  sinus 
than  those  of  the  others  it  is  called  Labiate  or  Lipped.  If  the  fissure 
proceeds  entirely  across  the  corolla,  cutting  off  the  lower  portion,  it 
becomes  One-lipped  (Fig.  105).  Otherwise  it  is  Bilabiate  or  Two-lipped 
(Fig.  111).  The  two  lips  are  denominated  respectively  the  Upper  or 
Inner  (a),  being  that  which  is  nearer  the  stem  of  the  plant  when  the 
flower  and  its  stem  are  standing  erect  and  without  any  twisting,  and 


THE  AURICLE  57 

the  Lower  or  Outer  {h).  It  is  always  of  iiii])ortaiice  to  note  the  number 
of  lobes  inchuled  in  each  Hp,  in  doinf;  which  the  student  may  be  misled 
either  by  chorisis,  one  or  more  extra  lobes  making  their  appearance, 
or,  far  more  frequently,  by  cohesion,  two  lobes  coalescing  into  one  so 
as  to  simulate  suppression.  Two  forms  of  the  bilabiate  corolla  are 
commonly  recognized — the  Ringent  in  which  the  lips  stand  widely 
apart  (Fig.  Ill),  and  the  Personate,  in  which  the  mouth  is  occluded 
(Fig.  109). 

Several  distinctive  titles  are  applied  to  flower-forms  which  are 
characteristic  of  large  and  important  families  or  sub-families,  the 
Labiate  being  one.  Another  is  the  Papilionaceous,  in  reference  to  its 
simulation  of  the  form  of  a  butterfly  (Papilio),  as  in  the  common  Pea 
(Fig.  110).  The  five  petals  are  as  follows:  Two  (a)  are  more  or  less 
coherent  by  their  lower  edges  to  form  the  Body  or  Keel;  two  others  (6) 
are  denominated  the  Wings;  the  fifth  (c)  is  large,  broad,  and  commonly 
reflexed  so  as  to  ajjpear  erect,  and  is  called  the  Vexillum  or  Standard. 

Caryophyllaceous  and  Cruciferous  Corollas. — Special  names  have  also 
been  applied  to  the  choripetalous  corollas  characteristic  of  the  pink 
and  mustard  families.  The  former,  the  Carophyllaceous  corolla  (Fig. 
72),  consists  of  five  petals,  each  with  a  long,  slender  claw  extending  to 
the  summit  of  an  elongated  calyx,  and  there  expanding  abruptly  into 
a  broad  limb.  The  other,  the  Cruciferous  corolla,  has  four  petals,  of 
similar  structure  and  form,  so  placed  as  to  present  the  form  of  a  cross. 

Appendages. — Appendages  to  the  perigone,  while  less  numerous  and 
varied  than  in  the  case  of  the  other  organs,  call  for  our  careful  attention, 
as  they  sometimes  occasion  false  interpretations.  In  the  sense  in  which 
the  term  is  here  emi)loyed,  we  do  not  refer  to  hairs  and  similar  out- 
growths which  modify  the  surface  of  the  parts,  and  which  pertain 
equally  to  other  parts  of  the  ])lant,  but  to  developments  which  pertain 
distinctly  to  the  flower,  modifying  its  structure  or  functions,  or  com- 
monly both,  in  some  important  way. 

The  Auricle. — In  Nicandra  (Fig.  113)  we  observe  a  slight  appendage 
at  the  base  of  the  calyx-lobe  on  either  side  and  directed  downward. 
Such  an  appendage,  because  of  its  resemblance  to  the  lobe  of  the  ear, 
is  called  an  Auricle.  Its  appearance  is  somewhat  exaggerated  in  this 
case,  owiiiu:  to  tlu-  fact  that  the  calyx  is  inflated.  Smaller  auricles  are 
seen  at  the  base  of  the  calyx  of  Lobelia  (Fig.  1  ");'>) .  A  similar  a])pendage 
is  sometimes  directed  upward,  and  by  its  union  with  the  contiguous 
one  forms  an  organ  exactly  resembling  an  intermediate  or  false  sejial, 
as  in  the  Strawberry   (Fig.   30).     Such  ai)pendages,  which   undergo 


58  THE  PERIGONE 

considerable  variation  in  form  and  consistency,  may  or  may  not  be 
stipular  in  their  natnre.  Marginal  teeth  extended  into  conspicuous 
appendages  have  already  been  referred  to. 

The  Cauda  or  Tail. — Sometimes  the  apex  is  similarly  prolonged  into  a 
Cauda  or  Tail,  an  extremely  exaggerated  form  of  which  is  sometimes 
seen  (Fig.  115). 

The  Awn. — An  apex  extended  into  an  acute,  stiff",  slender  point  is 
an  Arista  or  Awn  (Fig.  78,  a).  An  awn  sometimes  emanates  from  the 
producing  organ  at  the  back,  instead  of  at  the  apex,  and  is  then  called 
a  Dorsal  Awn. 

The  Horn.— An  awn-like  body  which  is  hollow  is  a  Cornu  or  Horn 
(Fig.  150,  a). 

The  Spur. — A  horn-like  appendage  extending  downward  is  called  a 
Calcar  or  Spur  (Fig.  65).  The  spur  may  also  be  dorsal  (Fig.  114).  All 
of  the  appendages  noticed  above  may  be  found  upon  either  calyx  or 
corolla. 

The  Fornicate  Corolla. — Sacs  to  the  corolla  are  sometimes  intruded, 
as  in  Mertensia  (Figs.  118  and  119),  instead  of  extruded.  The  corolla 
is  then  said  to  be  Fornicate.  Instead  of  sacs  there  may  be  longitudinal 
folds,  as  in  some  species  of  Gentian. 

The  Palate. — When  a  single  large  sac  occludes  the  mouth  of  a  bilabi- 
ate corolla  it  is  called  a  Palate  (Fig.  94,  d). 

jNIany  appendages  such  as  we  have  noticed  are  secretory  in  function 
and  they  may  even  be  glandular  in  form.  Doubtless  the  various 
secretions  are  characteristic,  and  might,  in  pharmacy,  in  exceptional 
cases,  be  utilized  for  diagnostic  purposes,  but  the  attempt  has  never 
yet  been  made. 

The  Corona  or  Crown. — Lastly,  we  note  what  is  perhaps  the  most 
important,  as  it  certainly  is  the  most  striking  and  interesting,  of  the 
corolla  or  calyx  appendages — namely,  the  Crown.  The  crown  is  an 
outgrowth,  more  or  less  membranaceous,  from  the  face  of  the  perigone. 
Its  morphological  nature  is  not  understood  or  agreed  upon,  and  is 
probably  not  the  same  in  all  cases.  It  may  be  a  mere  abnormal  product 
of  median  chorisis,  or  it  may  be  the  homologue  of  the  ligule  of  certain 
leaves,  hereafter  to  be  considered  (see  h  in  Fig.  4G5,  .1),  the  latter  being 
regarded  as  a  normal  and  morphologically  distinct  part.  When  the 
crown  develops  from  a  petal  with  a  distinct  narrowed  basal  portion, 
which  may  be  assumed  to  correspond  to  the  petiole  of  the  formative 
leaf,  it  usually  develops  from  or  near  the  point  where  this  is  joined 
to  the  broader  portion  (Fig.  IS).    The  crown  becomes  very  important 


PRAEFLORATION 


50 


ill  classification  in  such  families  as  Passifloraceae  (Fij?.  110,  a),  Asclc- 
])iadaccac,  and  AiiKiri/llidaccac  (Fif?.  117,  a).  A  ring  of  intruded  folds 
at  the  throat  (Fijj;.  119)  is  often,  jjcrliaps  incorrectly,  called  a  crown. 
It  is  sometimes  very  difficult  to  deterniine  whether  the  crown  is  an 
appendage  of  the  corolla  or  of  the  androecium.'  Its  adhesion  is  some- 
times to  the  androecium  and  not  to  the  corolla,  and  sometimes  to  both. 
In  some  species  of  Passi/lom  which  have  no  corolla,  the  attachment 
is  to  the  calvx  onlv. 


//a 


Fig.  IIG.  T,i>nKitutlinal  section,  throviKli  flower  of  Passiflora  oxliihiting  orown  at  a.  117.  Flower  of 
Narcissus  exliibiting  a.  large  crown  at  a.  US.  Flower  of  Myoyotis.  11',).  The  same  opened  to  sliow 
folds  in  throat. 


Praefioration. — The  arrangement  of  the  ])arts  of  the  perigone  in  the 
bud  yields  some  of  our  most  important  diagnostic  characters  as  dis- 
tinguishing families,  sub-families  and  genera,  and  has  been  the  subject 
of  elaborate  classification.  The  demands  of  pharmacognosy,  however, 
call  for  attention  to  only  the  princii)al  types  of  Praefioration  or  Aesti- 
vation. The  three  principal  types  depend  upon  the  fact  that  the  com- 
bined breadth  of  all  the  ])arts  of  a  perigone  circle  must  (1 )  be  insufficient 
to  enclose  the  i)U(l,  in  which  case  ()])en  s])accs  must  be  left  between 
their  margins  {Rr.srdd)  or  the  summit  must  be  left  uncovered  (the  calyx 
in  P^ig.  120),  the  form  in  either  case  being  called  Open;  (2)  it  must  be 
exactly  sufficient  to  enclose  it,  the  edges  then  meeting  exactly,  with 
nothing  to  spare  and  the  form  being  called  Valvate  (Fig.  12;),  the  calyx); 
or  {'.])  it  must  be  excessive,  in  which  case  the  excess  may  be  dis])()sed 
of  in  one  of  several  ways.  In  one,  the  parts,  after  nuH-ting  s(iuarely, 
ar<'  uniformly  turned  straight  outward  (Fig.  121),  the  form  being 
called  Valvate  Reduplicate.  In  another,  they  are  turned  straight 
inward,  the  Valvate  Iiiduplicate  form  (Fig.  122).    They  may  even  be 


60 


THE  PERIGONE 


rolled  inward,  the  Involute  form.  When  lapping  the  one  o^•er  the 
other  they  are  Imbricate  (Fig.  123,  the  corolla).  Here  it  is  important 
to  note  whether  the  overlapping  is  from  right  to  left,  Dextrorse  (Fig. 
125),  or  the  reverse,  Sinistrorse  (Fig.  124).  In  determining  this  point, 
the  relations  can  best  be  understood  by  imagining  the  flower  as  a  man, 
his  feet  in  the  direction  of  the  torus  and  his  hands  representing  the 
petals.  To  be  dextrorse,  his  right  hand  must  be  covered  by  his  left. 
In  other  words,  the  terms  "right"  and  "left,"  in  this  position,  signify 
right-covered  and  left-covered,  not  right-covering  and  left-covering. 


/Z3.     /2& 


Fig.  120.  Bud  of  Ipomoea  with  open  calyx  and  convolute  corolla.  121.  Transverse  section  through 
valvate  reduplicate  calyx  of  Hibiscus.  Fig.  122.  The  same,  valvate-induplicate  calyx  of  Clematis. 
124.  Sinistrorse  imbrication  of  corolla-lobes  of  Lochnera.  125.  Dextrorse  imbrication  of  corolla- 
lobea  of  Echites. 


Petals,  sepals,  or  stamens  are  occasionally  rolled  vertically  down- 
ward from  the  apex,  this  form  being  called  Circinate.  Occasionally  we 
find  the  petals  folded  and  doubled  in  an  irregular  manner,  the  Crumpled 
or  Corrugated  form  of  praefloration.  A  number  of  terms  are  called  for 
by  the  peculiar  conditions  of  the  gamopetalous  form.  Economy  of 
space  is  here  commonly  secured  by  longitudinal  folding,  the  Plaited 
form.  Vertical  shortening  is  often  secured  by  twisting,  the  Convolute 
form  (Fig.  120,  the  corolla).  In  this  case  it  is  important  to  determine 
the  direction  of  the  contortion  as  dextrorse  or  sinistrorse,  in  the  same 
way  as  that  of  imbrication. 

Other  details  as  to  the  precise  mode  of  overlapping  are  frequently 
worthy  of  note. 

In  determining  the  form  of  jjraefloration,  care  must  be  taken  to 
select  a  well-formed  bud. 

The  Mixed  Form. — The  praefloration  may  be  mixed,  as  in  Oenothera, 
where  the  parts^^are  valvate  at  the  base  and  slightly  imbricate  or  redu- 
plicate at  the  immature  apex.  At  the  best,  intermediate  and  perplexing 
forms  will  be  encountered. 


DURATION  61 

Duration. — The  duration  of  the  perigone,  especially  of  the  calyx, 
is  frequently  of  considerable  importance  from  the  standpoint  of  phar- 
macognosy, although  in  general  not  so.  When  a  part  falls  away  at, 
or  very  shortly  after,  expansion  it  is  Caducous.  When  lasting  about 
a  day,  and  then  either  falling  or  i)erishing  upon  the  flower,  as  in  the 
poppy,  it  is  Fugacious.  When  lasting  longer  than  a  day,  but  falling 
soon  after  fertilization,  it  is  Deciduous.  When  remaining  and  retaining 
more  or  less  of  its  normal  appearance  for  some  time  after  fertilization, 
it  is  Persistent.  When  so  remaining,  but  in  a  withered  condition,  it  is 
Marcescent.  These  definitions  assume  that  fertilization  takes  place 
normally.  If  this  be  artificially  prevented  or  deferred,  the  freshness  of 
a  corolla  is  often  very  greatly  })rol()nged.  (See  Fertilization.)  Impor- 
tant facts  relating  to  the  Accrescent  calyx  of  the  fruit  will  be  i^resented 
when  the  latter  is  discussed. 

Some  very  interesting  facts  concerning  characteristic  movements 
of  the  corolla,  its  sleeping  and  awakening  and  other  habits,  should  be 
sought  in  general  works  on  botany. 


CHAPTER  V 

THE  ANDROECIUM 

Review. — It  has  already  been  shown,  in  considering  the  general 
nature  of  the  flower,  that  in  at  least  a  large  part  of  the  flowering  class, 
the  androeciiim  typically  consists  of  two  stamen-circles,  the  stamens 
of  each  isomerous  with  the  parts  of  the  other  circles,  one  standing  in 
front  of  each  petal  and  sepal,  that  each  stamen  is  entirely  free  and 
distinct,  and  of  characteristic  form  and  structure  (Figs.  12  and  14). 
We  have  also  pointed  out  some  of  the  forms  of  deviation  due  to 
duplication,  suppression,  adhesion,  and  metamorphosis.  To  these  the 
following  general  remarks  may  be  added. 

Sterile  Filaments  and  Anthers. — When  an  anther,  still  present,  has 
lost  its  function,  it  is  called  a  Sterile  or  Imperfect  Anther.  When  the 
anther  has  become  suppressed,  but  the  filament  remains,  the  latter  is 
called  a  Sterile  Filament.  Either  of  these  is  called  a  Staminodium. 
One  or  more  complete  circles  of  sterile  filaments,  changed  or  not  by 
metamorphosis,  may  be  mistaken  for  a  crown  or  a  disk  (Fig.  38). 
Adhesion  of  the  stamens  to  the  corolla,  or  even  to  the  ovary,  may 
include  only  one  circle,  the  other  circle  being  entirely  free,  or  they  may 
be  adnate  in  different  degrees  (Fig.  44). 

Terms  Indicating  the  Number  of  Stamens. — Before  discussing  other 
and  specific  points  of  variation,  we  shall  consider  the  typical  organ 
more  in  detail.  The  number  of  stamens  in  the  androecium  is  indicated 
by  joining  the  appropriate  numeral  to  the  suffix  "androus;"  thus, 
Monandrous,  Diandrous,  Triandrous,  Tetrandrous,  Pentandrous,  etc. 
These  terms  do  not  necessarily  indicate  the  numerical  ])lan  of  the  flower. 
When  the  number  is  20  or  more,  the  term  Polyandrous  or  Stamens 
Indefinite  is  commonly  employed. 

Color. — In  color,  the  filament  is  commonly  white  or  whitish,  and 
the  anther  yellow;  but  this  is  not  an  absolute  rule,  as  the  latter  is  often 
blue,  brown,  black,  or  otherwise  colored. 

Construction  of  the  Anther. — There  are  several  distinct  forms  of  attach- 
ment of  the  anther  to  its  filament  which  are  characteristic  of  larger  or 
smaller  groups.  Its  origin  from  the  leaf  assumes  that  each  theca 
corresponds  to  a  vertical  half  of  the  leaf  from  which  it  has  developed. 


ATTACHMENT  OF  THE  ANTHER 


63 


and  the  production  of  a  sccoiHlan-  or  "false"  i)artition  separating  each 
theca  h)ngitudinally  into  two  locclli.  This  inipHes  a  four-h)cellatc 
condition  of  all  anthers  (Fig.  K)S).  Ordinarily  this  condition  is  not 
permanent,  the  false  septa  more  or  less  completely  (lisa])i)earing  after 
the  formation  of  the  pollen,  leaving  the  mature,  antlier  two-celled,  or 
this  condition  is  brought  about  in  other  ways. 

Attachment  of  the  Anther. —  The  Adnaic  Form.—  It  is  furthermore 
assumed  that  the  filament  is  normally  continued  along  the  back  of 
the  anther  in  the  relation  of  the  midrib  of  the  formative  leaf.  This 
form  of  attachment  is  called  Adnate  (Fig.  ]2()). 


Fig.  126.  Adnate  anther  of  Magnolia.  127.  An  incumbent  anther.  128.  Twisted  anther  of  Ceiba. 
129.  Versatile  anther  of  Oenothera.  130.  Innate  anther  of  Sangumaria.  131.  Reniform  confluent 
anther  of  Malva.     132.  Horizontal  confluent  anther  of  Pcnlslemon.     133.  Sagittate  anther  of  Taber- 

naemontana. 


Iiicinnhctit  Form. — It  ma>'  be  attached  only  at  some  ])oint  u])()n  the 
back  (I)orsifixed).  Of  this  there  are  two  forms.  In  one  (Fig.  127)  the 
anther  is  rigidly  fixed,  its  lower  portion  close  to  and  ])arallel  with  but 
free  from  the  upper  portion  of  the  filament,  the  Incumbent  form. 

]'ers(iiUe  Form. — In  the  other,  it  moves  freely  upon  the  pivotal 
l)()int  of  attachment  (Fig.  129),  the  Versatile  form.  Rarely  the  anther 
is  wrapped  or  twi.sted  about  its  filament  (Fig.  128). 

Innate  Form.— Thv  continuation  of  the  filament,  instead  of  being 
along  the  back,  may  be  centrally  up  through  the  base  and  between  the 
thecae  (Fig.  130),  the  Innate  form. 

SiiKjiiidtc  Form. — The  lower  ])ortions  of  the  thecae  may  be  separated 
from  one  another  and  from  the  connective  (Fig.  13.3),  the  Sagittate  form. 

Reniform  (inti  Ilor/'jnifdl  Form.^-. —  The  sagittate  condition  is  some- 
times extreme,  the  antliers  becoming  more  or  less  reiiifonn  (Fig.  131) 
or  semicircular,  or  tlicy  may  e\fii  become  liori/.ontal    I  l''ig.  132).    This 


64  THE  ANDROECIUM 

is  to  be  distinguished  from  the  form  which  is  horizontal  by  versatility 
(Fig.  129),  by  the  presence  in  the  latter  of  the  two  cells  side  by  side, 
in  the  former,  end  to  end. 

Extrorse  and  Introrse  Attachments.- — Rarely  the  adnate  form  will 
possess  the  connective  upon  the  inner  side  (next  the  pistil),  when  it  is 
Extrorse  by  Attachment,  in  the  normal  form  being  Introrse. 

Forms  of  the  Filament. — Besides  these  variations  in  the  relation  of 
filament  and  anther,  each  is  in  itself  subject  to  certain  modifications, 
some  of  which  will  be  discussed  in  connection  with  appendages  and 
exaggerated  growth.  The  general  form  of  the  filament  is  subject  to 
much  variation  which,  being  characteristic  in  a  given  species  or  genus, 
requires  specification.  When  cylindrical,  either  of  uniform  thickness 
throughout  or  regularly  tapering,  it  is  Terete.  When  considerably 
thickened  toward  and  at  the  summit,  so  as  to  be  club-shaped,  it  is 
called  Clavate.  When  flattened  it  is  Complanate.  Laterally  Com- 
planate  is  so  flattened  that  the  edges  point  toward  and  from  the  gynae- 
cium,  the  broad  sides  to  right  and  left.  Dorsally  complanate  has  the 
edges  pointing  to  right  and  left,  the  broad  sides  facing  toward  and  from 
the  gynaecium.  A  dorsally  complanate  filament  may  have  a  sharp 
ridge  or  keel  running  along  its  back,  when  it  is  called  Carinate  or  Keeled. 
If  the  ridge  is  less  sharp  and  prominent  it  is  Costate  or  Ribbed.  It 
may,  upon  the  other  hand,  bear  a  groove,  when  it  is  called  Channelled. 
Rarely  a  filament  is  Triangulate  in  cross-section,  or  otherwise  prismatic. 
When  tapering  from  a  broad  base  to  a  rather  acute  apex,  and  rather 
short,  it  is  Subulate  or  awl-shaped.  When  very  slender  or  thread- 
shaped,  it  is  filiform.  When  even  more  slender  so  as  to  be  hair-like, 
it  is  Capillary. 

Forms  of  the  Anther. — The  principal  forms  of  anther  are  oblong,  oval, 
globular,  reniform,  quadrangular,  or  linear,  and  the  base  or  apex  may 
be  truncate,  rounded,  obtuse,  acute,  or  pointed.  An  anther  is  occa- 
sionally doubled  upon  itself,  when  it  is  styled  Sinuous  (Fig.  139).  It 
may  even  take  the  form  of  a  horizontal  ring  (Fig.  134).  This  condition 
is  sometimes  preceded  by  the  loss  of  one  theca.  In  any  case  of  curva- 
ture, even  slight,  of  the  anther,  the  same  is  characteristic  and  of  value 
in  classification,  as  exemplified  in  the  vast  genus  Solanuvi,  where 
attention  to  this  character  is  well  nigh  indispensable.  The  filament  is 
also  sometimes  variously  curved  or  reduplicate,  and  this  condition  may 
be  permanent  or  only  temporary  during  the  early  stage  of  the  flower, 
as  in  Ardostaphylos  (Fig.  145),  where  the  powerful  elasticity  of  the 
filament  assists  in  expanding  the  corolla. 


J.\TR()/iSK   A\D  EXTliOR>SK   DI'JII ISCKXCK 


05 


Development  of  the  Spores. — Inside  of  the  tlicca,  develop  certain 
large  cells,  in  rows,  the  Spore  INIother  Cells,  each  of  which,  by  t)\ice 
dividing,  produces  a  Tetrad  of  four  pollen-grains.  Ordinarily  the  wall 
of  the  mother-cell  mostly  (lisa])i)ears  and  leaves  the  grains  separate  and 
mobile,  while  in  other  cases  they  cohere  in  the  tetrad  or  in  a  cluster 
of  tetrads. 

Pollinia  and  PoUinaria. — Large  clusters  are  called  Pollinia  or  Pollen- 
masses.  The  entire  contents  of  a  theca  may  form  one  pollinium  (Fig. 
135),  or  they  may  be  divided  into  several  (Fig.  140).  A  cluster  of 
pollinia,  like  the  last,  is  called  a  Pollinarium.    The  number  of  pollinia 


Fig.  134.  Ring-formed  anther  of  Cyclanthera.  135.  Pollinium  of  Asclepias.  136.  Dorsal  dehiscence 
in  anther  of  Hyoscyamus.  137.  Dehiscence  by  apical  pores  in  Menzicsia.  138,  Dehiscence  by  valves 
in  anther  of  Sassafras.  139.  Sinuous  anther  of  Sicyos.  140.  Pollinarium  of  4  pollinia  in  Ponthiera. 
141.  Marginal  dehiscence  in  anther  of  Convallaria.  142.  Ventral  dehiscence  in  anther  of  tomato. 
143.  Dehiscence  by  apical  pores  in  anther  of  Cassia.  144.  Peculiar  ventral  pores.  145.  Apical  pores 
becoming  basal  by  inversion  of  the  anther  in  Arctostaphylos. 


in  a  theca  is  of  much  diagnostic  importance  in  tlie  Orchidaceae,  The 
characteristics  of  the  individual  ])()llen-grains  are  of  the  utmost  value 
in  pharmacognosy,  as  well  as  in  classification  (as,  for  instance,  in  the 
Acanthaceae) ,  and  arc  discussed  in  works  on  histology. 

Dehiscence  of  the  Anther. — ^We  must  next  consider  the  structural 
provisions  for  permitting  the  escape  of  the  pollen  from  the  thecae  or 
locellae.  This  is  commonly  by  splitting,  called  Dehiscence,  along  a 
longitudinal  line  upon  each  theca,  called  the  Suture.  If  the  suture  is 
at  the  back  of  the  anther,  as  in  Ilyoscyamns  (Fig.  136),  the  dehiscence 
is  called  Dorsal.  If  upon  the  face,  as  in  the  tomato  (Fig.  142),  Ventral; 
if  upon  the  i^^h^(.\  as  in  Coiirdllaria  (Fig.  141),  ^Marginal. 

Introrse  and  Extrorse  Dehiscence. — This  suture  may  face  the  gynae- 
cium,  when  the  anther  is  Introrse  by  Dehiscence,  or  away  from  it, 
5 


66  THE  ANDROECIUM  ^ 

Extrorse  by  Dehiscence.  It  does  not  follow  that  an  anther  introrse  or 
extrorse  by  dehiscence  is  the  same  by  attachment. 

Confluent  Sutures. — In  the  sagittate-horizontal  anther  the  sutures 
of  the  two  thecae  often  become  continuous,  the  Confluent  form  (Figs. 
131  and  132). 

Dehiscence  by  Pores. — Small  orifices,  called  Pores,  frequently  exist  at 
the  apex,  as  in  Ca.s-.sia  (Fig.  143),  more  rarely  at  the  base.  The  most 
scrupulous  care  must  be  taken  to  determine  the  exact  direction  in  which 
apical  pores  look.  In  some  cases,  as  in  Solanum,  a  slight  difference 
will  possess  specific  importance. 

Dehiscence  by  Valves. — A  less  common  form  of  discharge  is  by  A^alves 
(Fig.  138),  the  common  form  for  the  four-locellate  anther.  Special 
mechanical  contrivances  for  aiding  in  the  discharge  of  the  pollen  are 
of  great  interest  and  will  be  mentioned  under  Cross-pollination. 

Cohesion. — Cohesion  is  responsilile  for  quite  as  great  and  important 
modifications  of  the  androecium  as  of  the  perigone.  Here,  as  there,  it 
may  be  complete,  or,  beginning  at  either  apex  or  base,  it  may  stop  at 
any  point.  Fig.  84  displays  the  dilated  bases  of  the  filaments  of 
Lysimachia  lightly  coherent,  the  detection  of  the  condition  calling 
for  the  same  keen  inspection  as  in  the  case  of  the  corolla.  In  Guarea 
(Fig.  147)  the  union  is  seen  carried  to  the  anthers,  but  these  left 
distinct. 

Adelphism. — Coherent  filaments  are  styled  Monadelphous  when  all 
united  (Fig.  147),  Diadelphous,  when  there  are  two  groups,  even  though 
one  of  them  contains  but  one  stamen,  as  in  Glycerrhiza  (Fig.  146), 
Triadelphous  when  three,  and  so  on.  It  must  not  be  lost  sight  of  that 
the  terms  are  applied  similarly,  w^hether  the  iniion  is  progressive,  the 
result  of  cohesion  as  in  this  case,  or  that  of  incomplete  chorisis,  as  in  the 
Tilia  (Pigs.  34  and  37)  and  Psorospermum  (Fig.  38),  though  its  classi- 
ficatory  value  is  very  different  in  the  two  cases. 

The  Stamen-column. — The  term  column,  previously  explained,  is 
changed  to  Stamen-column  for  monadelphous  stamens. 

The  Ssmandrium. — The  stamen-column  is  ordinarily  hollow,  contain- 
ing the  Gynaecium;  but  when  the  flower  is  staminate,  the  column  is 
solid,  and  called  a  Synandrium. 

When,  as  seen  in  Fig.  92,  the  anthers  come  together  but  do  not  actually 
cohere,  they  are  called  connivent.  The  cohesion  is  carried  only  partly 
down  the  filaments  in  the  squash  (Fig.  148),  and  partly  upward  in  the 
Sidalcea  (Fig.  149),  but  in  the  Asdepias  (Fig.  154)  it  is  complete  for 
the  entire  organs. 


APPEND  AGING 


C7 


Asymmetry  and  Irregularity. — A  lack  of  symmetry  aiul   regularity, 

actinu'  sci)arately  or  tout'tluT,  is  responsible  for  a  number  of  character- 
istic and  iinpoi-tant  states  of  the  androecium  requiring,'  distinctive 
terms. 

The  Didynamous  Androecium.-  In  the  o-merous  flower  of  ScidcUarid 
(Fii;-.  l")!)  six  stamens  are  su])pressed  and  the  rcniaininijj  four  are 
irr('<;ulai-,  there  being  a  pair  of  each  form.  This  foi-ni  of  anch'oeciiim 
has  received  the  title  of  Didynamous.  In  this  case  the  antlicrs  of  a  j)air 
are  connivent  also. 


/J4 


Fig.  140.  Diadelphous  arulroerium  of  Glycyrrhiza.  1-17.  Vertical  section  lliroiigh  flower  of  Guarea, 
showing  nionadelphous  filaments  witli  distinct  anthers.  148.  Cohesion  of  filaments,  incomplete  at 
base,  in  flower  of  squash.  149.  The  same,  incomplete  at  summit,  in  flower  of  SiV/afcca.  150.  Vertical 
section  through  flower  of  Asdepias  showing  coherent  filaments  and  anthers,  with  appendages  to  crown 
in  form  of  horns.  154.  Winged  androecium  of  same.  151.  Didynamous  androecium  of  Labiatae 
152.  Androecium  of  Eupatorium,  the  anthers  coherent,  the  filamenta  distinct.  153.  Monadelphous 
filaments  and  anthers  of  Lobelia. 


The  Tetradynamous  Androecium.^In  that  of  the  IMustard  (Fig.  33), 
two  of  the  stamens  Iuinc  each  by  chorisis  become  converted  into  two, 
these  differing  in  length  from  the  undi\i(led  pair.  'J'his  form  is  styled 
Tetraflynanions. 

Appendaging.  No  other  subject  connected  with  the  androecium  calls 
for  such  close  and  discriminating  attention  in  connection  with  pharma- 
cognosy as  the  i)roducts  of  exaggerated  growth  and  enation.  No 
portion  of  the  androecium  is  free  from  their  effects,  which  ai)ply  equally 
to  it  when  adherent  or  coherent,  free  or  distinct.  The  simplest  form 
of  appendage  to  the  filament  is  that  of  sti])nloid  a])])endages  to  the 


68 


THE  ANDROECIUM 


base,  called  Petaloid  when  assuming  the  form  of  a  petal,  as  in  Fig.  155 
A  similar  appendage  may  stand  in  front  of  a  stamen.  One  standing  in 
front  of  a  stamen  group  has  been  shown  in  Fig.  37.  Appendages  may 
be  developed  at  a  higher  point  in  other  cases.  Appendages  in  the  form 
of  teeth  or  hairs  are  very  common. 

Modifications  of  the  Connective. — Modifications  of  the  connective  are 
numerous  and  remarkable.  The  thickening  of  its  entire  body,  equally 
or  unequally,  produces  such  appearances  as  are  seen  in  Figs.  15G,  157, 
and  159.  Or  the  extension  may  result  in  elongation  either  above  or 
below  the  thecae,  instead  of  in  broadening. 


/SS.  2S6  ISZ       IMJ60 


Fig.  155.  Petaloid  appendage  to  filament  of  Chaetostoma.  156,  157,  and  159.  Anthers  with  the  con- 
nective broadened  so  as  to  separate  the  thecae.  158.  The  same  with  the  broadened  connective  forked. 
160.  Stamen  with  connective  extended  between  the  apex  of  the  filament  (a)  and  the  base  of  the  anther 
(6).  161.  The  same,  with  an  appendage  at  base  of  connective.  162  and  163.  The  appendage  with 
scarcely  any  elongation  of  connective.  16-4.  Forked  connective  of  Salvia,  each  branch  bearing  one  of 
the  thecae. 


Basal  Appendages. — If  the  extension  is  downward,  it  will  lead  to  an 
apparent  jointing  of  the  filament  (Fig.  160),  the  space  between  a  and  b 
being  such  a  downwardly  produced  extension  of  the  connective.  A 
slight  bulbous  enlargement  at  the  base  may  be  modified  into  the  most 
grotesque  forms,  as  shown  in  Figs.  161  to  163.  Such  appendages,  in 
every  detail  of  number,  form,  position,  and  direction,  are  characteristic, 
and  in  a  family  like  the  Melastomaceae,  from  which  most  of  the  above 
illustrations  are  taken,  possess  generic  value.  Instead  of  elongating 
as  a  single  body,  the  base  may* apparently  divide  longitudinally,  through 
extreme  broadening,  resembling  a  forked  filament,  one  theca  borne  on 
each  branch  (Figs.  158  and  164.) 

One-celled  Anthers. — When  one  of  the  thecae  then  becomes  suppressed, 
its  connective  branch  remaining  (Fig.  165)  or  even  disappearing  (Fig. 
166),  one  of  the  forms  of  the  one-celled  anther  results.  Another  form 
is  produced  by  simple  abortion,  without  any  such  modification  of  the 
connective,  or  it  may  result  from  the  disappearance  of  the  connective. 


APPENDAGES  TO   THE  STAMEX  COIAMX 


G9 


Dorsal  Appendages.— Instead  of  the  base,  tlie  back  of  the  connective 
may  l)e  api)cii(Ia<;c(l.  It  may  become  expanded  into  a  disk-like  form 
over  the  backs  of  the  thecae,  as  in  Gratiola  (Fig.  1()7).  The  backs  of 
the  anthers  may  be  excavated  to  receive  it,  as  in  Aloe  (Fig.  108),  or  it 
may  be  ap})en(higed  in  any  other  direction. 

Apical  Appendages. — Appendages  of  any  form  may  devek)p  at  its 
ai)cx.  In  tlie  Compositae  these  are  frequently  triangular,  as  in  Eupa- 
toriuvi  (Fig.  109,  a),  or  lance-shaped.  In  the  Asariim  (Fig.  170)  it  is 
an  awn,  while  in  the  Violet  (Fig.  171)  it  is  sail-shaped.  Sometimes 
it  is  formed  like  a  feather  (Plumose). 


Fig.  165.  Forked  connective,  one  of  the  thecae  aborted.  IGG.  The  same  as  in  Audibertia,  with  one 
of  the  branches  aborted.  167.  Anther  of  Gratiola,  the  connective  expanded  into  a  saucer-shaped  disk. 
168.  Anther  of  Aloe,  the  connective  hollowed  to  receive  the  filament.  169.  Anther  of  Eupatorium, 
the  connective  bearing  a  terminal  appendage.  170.  The  same,  as  in  Asarum.  171.  The  same,  as  in 
Viola.  172.  Anther  of  Vaccitiium,  the  thecae  extended  into  awns  and  bearing  also  dorsal  awns.  173. 
Monadelplious  filaments  of  Alternanthera  bearing  fimbriate  appendages  in  the  sinuses. 


Appendages  to  the  Thecae. — It  remains  to  be  pointed  out  that  the 
thecae  themselves  may  be  similarly  appendaged  at  any  part.  Fig.  133 
displays  caudae,  or  tails,  which  are  found  in  a  great  variety  of  forms. 
In  Fig.  154,  a,  Alae,  or  wings,  are  illustrated.  Dorsal  spurs  or  claws 
(Calcaria)  frequently  occur  and  are  also  often  borne  at  the  top.  Apical 
awns  to  the  thecae,  forked  and  pore-bearing  at  the  summit,  as  well  as 
dorsal  awns,  are  also  shown  in  Fig.  172. 

Appendages  to  the  Stamen-column. — The  stamen-column  itself  is 
subject  to  reinarkai)le  and  characteristic  appendaging,  with  or  without 
connection  with  an  adnate  disk.  Ordinarily,  the  summit  of  the  stamen- 
tube  terminates  at  the  beginning  of  the  distinct  i)ortion  of  the  stamens, 
but  sometimes,  as  very  generally  in  the  Amaranthaccae  (Fig.  173),  it 
is  continued  ui)ward  in  the  sinuses  of  the  anthers,  and  this  j)()rti()ii  may 
be  lobed  and  appendaged  in  the  most  beautiful  manner. 

Stamens  which  extend  beyond  the  margin  of  the  coiojla  are  called 
Exserted  or  Plxsert.  This  term  is  also  ai)plieable  to  any  organ  which 
projects  beyond  the  perigone. 


CHAPTER    VI 

THE  GYNAECIUM 


Gymnospermous  and  Angiospermous  Gynaecia. — Two  distinct  types 
of  the  gynaecium  respectively  characterize  the  Gymnosperms  and  the 
Angiosperms,  both  of  which  classes  contribute  important  medicinal 
plants.  What  has  been  said  of  the  gynaecium  in  our  consideration  of 
the  general  nature  of  the  flower,  pertains  wholly  to  the  latter  class.  A 
few  words  concerning  the  former  may  be  written  before  taking  up  our 
detailed  study  of  the  latter. 

The  Gymnospermous  Pistil. — The  essential  character  of  the  gymno- 
spermous pistil  is  illustrated  in  Fig.  174.  This  consists  in  its  not  being 
shaped  into  an  enclosure  for  containing  the  ovules.     In  the  form  here 

figured  there  is  no  progress  toward 
such  a  condition,  the  carpel  remain- 
ing more  or  less  fiat  and  bearing  the 
ovules  upon  its  surface;  but  in  the 
progressive  forms  there  is  a  cavity, 
which,  however,  is  never  completely 
enclosed.  A  high  development  of  it 
is  found  in  the  Taxus  or  Yew  (Fig. 
175),  in  which  the  cavity  is  deep  and 

Fig.  174.    Entirely  plane  gymnospermous      OpCU    Ouly    at    the    Very    apCX.       The 

pseudo-cavity  of  the  gymnospermous 
carpel  is  never  divided.  It  is  evi- 
dent that  no  true  style  or  stigma  can  exist  in  this  class  of  plants, 
although  it  must  be  understood  that  there  is  an  organ  performing  the 
same  function  of  providing  for  the  germination  and  growth  of  the 
microspore,  the  possession  of  such  an  organ  being  the  one  distinction 
between  the  flowering  and  flowerless  plants. 

Review. — It  has  been  shown  that  the  gynaecium  of  Angiosperms, 
except  in  those  rare  cases  in  which  a  central  appendage  of  the  torus  is 
projected  u])ward,  occupies  the  center  or  summit  of  the  flower;  that  it 
consists  of  one  or  more  carpels  or  carpophylls  which  may  be  all  coherent 
into  a  single  ])istil,  the  Syncarpous,  Gamocarpous  or  Compound  Pistil 
(Fig.  2 IS,  etc.),  or  may  each  form  a  separate  pistil,  the  Apocarpous, 


carpel  of  Pinus.      175.  Cup-shaped  gymno- 
spermous carpel  of  Taxus. 


METHOD  OF  KXAMIXATJOX  71 

Monocarpellary,  orSiini)le  Pistil  (Figs.  219  and  220),  and  tlint  ordinarily 
the  carpels  alternate  with  the  stamens  of  the  adjacent  circle.  The  parts 
of  the  pistil  have  been  defined,  and  it  has  been  shown  that  of  these  the 
stipe  or  thecaphore  is  rarely  present,  and  that  the  style  is  very  fre- 
quently absent,  resulting  in  the  Sessile  Stigma.  The  different  forms  of 
adhesion  and  its  effects,  as  well  as  those  of  suppression  and  metamor- 
phosis, have  also  been  explained.  Some  additional  facts  of  a  general 
nature  must  be  considered  before  taking  up  the  details  of  this  subject. 
Method  of  Examination. — The  student  should  from  the  outset  resist 
the  temi)tation  to  seek  the  characters  of  the  gynaecium  in  the  mature 
or  immature  fruit,  because  of  its  more  convenient  size.  While  many 
of  the  characters  of  the  gynaecium  are  permanent,  there  are  others 
which  (lisai)])ear  after  the  fertilization  of  the  ovules,  and  still  others 
which  only  then  make  their  appearance.  The  other  ])arts  of  the  flower 
should  be  completely  stripped  oft",  this  operation  being  performed  under 
close  and  continuous  scrutiny,  with  the  idea  of  detecting  any  character- 
istics of  relationship  between  them  and  the  gynaecium.  The  latter 
should  then  be  carefully  examined  in  situ.  An  implement  should  be 
passed  down  between  the  carpels  to  determine  what  degree  of  cohesion, 
if  any,  exists  between  them,  for  this  will  occasionally  be  found  at  the 
very  base  only,  and  also  to  determine  if  there  be  any  adhesion  to  a 
central  prolongation  of  the  torus.  The  details  of  attachment  to  the 
torus  must  also  be  determined  and  their  arrangement  considered. 
When  numerous,  the  pistils  are  apt  to  assume  the  spiral  arrangement, 
which  has  already  been  noticed  in  referring  to  the  position  of  floral 
l)arts  in  general.  When  solitary,  the  carpel  assumes  a  position  to  one 
side  of  the  axis,  thus  demonstrating  its  isolation  through  the  suppres- 
sion of  the  complementary  ])arts  of  the  circle.  A  lack  of  uniformity, 
as  indicating  abortion  of  one  or  more  carpels,  must  be  looked  for. 
When  all  are  uniformly  aborted,  in  the  case  of  flowers  which  are  herma- 
j)hro(lite  but  imi)crfect,  this  fact  will  sometimes  escajic  detection  unless 
both  forms  of  flower  are  examined.  The  color,  texture,  and  surface  of 
the  carjx'Is  call  for  minute  exaiiiination  in  all  cases,  though  there  are 
no  peculiarities  of  a  general  nature  diil'ering  from  those  of  the  other 
organs.  As  in  the  case  of  the  petals,  so  in  that  of  the  carpels,  the  general 
form  is  determined  by  that  of  the  foliage  leaves;  but  the  form  is  less 
closely  preserved  and  the  homology  is  far  less  a])])arent  here  than  there, 
owing  to  the  far  more  ])r()foun(l  modifications  which  are  rendered 
necessary  by  the  j)eculiar  functions  of  the  carpels,  a  consideration  which 
will  further  on  be  seen  to  a])])ly  with  special  force  to  tin-  fruiting  stage. 


72 


THE  GYNAECTUM 


Position  of  the  Style.— The  position  of  the  style  often  calls  for  scrutiny. 
It  does  not  always  rise,  as  would  be  expected,  from  the  summit  of  the 
ovary.  One  process  by  which  deviation  in  this  particular  results  is 
illustrated  by  Fig.  17(5,  which  represents  the  deeply  lobed  ovary  of 
borage,  the  single  style  rising  from  the  depression  in  the  center.  If, 
now,  all  but  one  of  the  parts  of  such  an  ovary  were  to  become  aborted, 
the  style  would  be  seen  rising  more  or  less  laterally  (Figs.  177  and 
178),  or  even  basally  (Fig.  179)  from  the  remaining  monocarpellary 
ovary.  E\'en  though  the  styles  remain  separate  in  such  a  divided 
ovary,  yet  their  insertion  is  necessarily  carried  toward  the  base 
(Fig.  180). 


m.    J6'6.    m    js'S'    /m  wo 


Fig.  176.  Deeply  4-lobed  ovary  of  Boraffo.  177.  Lateral  style  on  carpel  of  I'VZ/oresia.  178.  The  same 
in  Aslronium,  the  style  almost  basal.  179.  The  same  in  Alchemilla,  the  style  completely  basal.  180. 
The  same,  with  none  of  the  carpels  aborted.  181.  Conical  style  of  Piper.  182.  Clavate  style  of 
Helianlhemum.  183.  Obconical  and  prismatic  style  of  Bomhax,  with  umbrella-shaped  stigma.  184. 
Obconical  style  of  Chimaphila.  185.  Filiform  styles  of  Poederia.  186.  Style  of  Potalia,  with  large 
bulb-like  base.  187.  Filiform  and  pilose  style  of  Galopina.  188.  Style  of  Heliocharis,  with  subulate 
branches.  189.  Styles  showing  a  tendency  to  early  separation  below,  while  remaining  coherent  above. 
190.  Capillary  style  of  maize. 


Forms  of  the  Style.— The  same  descriptive  terms  as  to  form  already 
applied  to  the  filament  apply  equally  to  the  style  and  its  branches. 
Owing  to  the  frequency  with  which  styles  are  coherent,  ribbed,  chan- 
nelled, or  angled  forms  are  common.  Fig.  181  illustrates  the  conical 
style  of  Piper,  Fig.  182,  an  obconical  one;  Fig.  183,  one  obconico- 


POSITION  AND  FORM  OF  STIGMA 


73 


prismatic;  Fig.  184,  a  clavate  form;  Fig.  18G,  one  with  a  bulbous  base. 
The  style  branches  in  Fig.  185  are  filiform;  in  Fig.  187  they  are  filiform 
and  plumose;  in  P'ig.  190,  cai)illary,  and  in  Fig.  188,  subulate.  Rarely, 
styles  will  be  connate  above,  distinct  below  (Fig.  189). 

Position  and  Form  of  Stigma. — The  position  and  form  of  the  stigma 
are  of  very  great  importance  in  classification.  Its  size,  as  compared 
with  that  in  other  related  plants,  is  apt  to  be  greater  or  less  according 
as  the  number  of  ovules  to  be  fertilized  varies. 


Figures  illustrating  forms  of  the  stigma 


The  Linear  Stigma. — It  has  already  ])een  sliown  that  while  the 
stigma  is  commonly  located  at  or  ii(>ar  the  ai)ex,  it  may  extend  either 
entire  or  divided  into  two  lines  for  a  greater  or  less  distance  down  the 
ventral  margin  of  the  style,  becoming  Linear  (Fig.  191). 

Stigmas  Introrsely  Located. — If  several  united  styles  are  separate 
at  the  summit,  or  ui)i)er  j)ortions,  their  stigmas  are  commonly  borne 
upon  their  inner  faces,  as  in  this  case,  and  are  frequently,  by  the  co- 
hesion of  the  former  in  the  young  condition,  secluded  from  the  access 
of  pollen  until  a  certain  time  (Figs.  191  and  271).     Between  the  con- 


74  THE  GYNAECIUM 

dition  of  complete  separation  and  complete  cohesion  of  several  stigmas 
there  are  all  degrees  of  division  and  of  lobing  of  the  divisions  (Figs.  192 
to  195). 

The  Capitate  Stigma. — ^A  stigma  which  is  strictly  terminal  and  more 
or  less  spherical,  thus  resembling  a  head,  is  Capitate  (Fig.  196). 

The  Truncate  Stigma. — The  Capitate  stigma  is  Truncate  when  it 
terminates  abruptly  in  a  flat  upper  surface,  as  though  cut  across  (Fig. 
197). 

The  Peltate  Stigma.— li  flattened  and  attached  at  the  center  it  is 
Peltate  (Figs.  183  and  198),  and  this  may  be  horizontal  or  oblique,  as 
in  the  latter.  The  peltate  stigma  may  have  its  margin  reflexed,  making 
it  umbrella-shaped  (Fig.  199),  or  upturned,  making  it  cup-shaped,  or 
Cupulate  (Fig.  200),  and  either  of  these  forms  may  be  lobed  (Figs.  201 
and  202). 

The  Laminar  Stigma. — A  stigma  flattened  out  into  a  blade-like  form 
is  called  Laminar.  Several  oblique  laminar  forms  are  show^n  in  Figs. 
20.3  to  205.  Fig.  207  displays  the  manner  in  which  the  stigma  sometimes 
enfolds  the  stamen. 

The  Annular  »Sii^7?ia.— Stigmas  sometimes  possess  a  ring  at  or  below 
the  apex,  the  Annular  form,  various  modifications  of  which,  unlobed 
and  lobed,  are  shown  in  Figs.  210  to  215.  Such  forms  prevail  in  the 
family  Ajjocynaceae  and  are  of  great  value  in  classification. 

Appendages  to  the  Stigma. — The  Appendages  of  the  stigma  are  quite 
as  numerous  and  varied  as  those  of  the  anther.  A  Plumose  appendage 
is  shown  in  Fig.  209.  Such  are  common  among  the  grasses.  A  stigma 
(or  other  organ)  is  called  Penicillate  when  its  ])lumose  appendage 
resembles  a  little  brush  (Fig.  208).  In  Stigmatophyllon,  the  appendage 
is  a  little  green  leaf  (Fig.  206). 

Terms  Indicating  the  Number  of  Carpels. — The  number  of  carpels  in  a 
compound  pistil  is  indicated  by  the  use  of  the  appropriate  numeral 
followed  by  the  suffix  "carpellary,"  thus  Dicarpellary,  Tricarpellary. 

Determination  of  the  Number  of  Carpels. — The  determination  of  the 
number  of  carpels  is  of  the  utmost  necessity,  but  is  usually  a  difficult 
task  for  the  beginner,  especially  if  he  is  not  pre\'iously  trained  in  the 
art  of  plant-dissection.  The  indications  may  be  divided  into  external 
and  internal.  The  latter  must  be  apprehended  from  the  study  of 
internal  structure  explained  below. 

External  Indications. — Whenever  there  is  more  than  one  pistil  in  a 
gynaecium,  each  consists  of  but  one  carpel.  Complete  chorisis  of  a 
carpel,  producing  more  than  one  pistil,  never  exists,  although  it  fre- 


IX  ri'JRNA  L  IN  Die  A  TIONS 


75 


queiitly  appears  so,  in  the  fruit.  If  cohesion  is  partial,  cxeii  tlioiif^h  so 
nearly  complete  as  to  Icaxc  a  separation  represented  by  a  mere  lohirig 
at  apex  (Fi<;;.  21G)  or  dorsum  (Figs.  217  and  218),  the  determination 
of  the  mimber  of  its  carpels  is  not  difficult.  It  is  true  that  the  latter 
condition  is  often  complicated  by  grooving  or  pseudo-lobing  pertaining 
to  the  backs  of  the  indi\i(lual  carpels,  but  such  grooves  are  usually 
characteristically  different  from  those  separating  the  carpels.  While 
the  above  remarks  have  been  applied  especially  to  the  ovary,  they  may 
be  applied  with  equal  force  to  the  styles  and  stigmas.  If  the  exterior 
of  the  ovary  bear  no  indications  of  the  number  of  car])els,  we  may 
count  the  styles,  or  the  divisions  or  apical  or  dorsal  lobes  of  a  style 
column,  and  if  those  be  wanting,  then  the  stigmas  or  the  corresponding 
characters  of  the  stigma.     It  must  be  noted,  however,  that  complete 


Fig.  21G.  Ovary  of  Modiola,  the  lobes  of  the  summit  indicating  the  carpels.      217.    TIk 
by  lateral  lobing  in  Pentapanax.     218.  The  same  in  Tetraplasandni. 


or  partial  chorisis  of  style  or  stigma  is  not  at  all  rare,  and  care  must  be 
taken  to  avoid  falling  into  error,  by  counting  mere  parts  as  styles  or 
stigmas.  In  such  case  the  number  of  lobes  of  each  is  apt  to  equal 
the  number  of  styles  or  stigmas. 

Internal  Indications. — In  the  case  of  failure  of  all  these  indications  to 
appear,  the  internal  structure  must  be  studied.  For  this  purpose  both 
longitudinal  and  transverse  sections  must  be  made.  The  former  should 
be  so  directed  as  to  lay  open  the  inside  of  a  cari)el,  and  of  the  latter 
there  should  be  three,  through  the  lower,  middle,  and  upper  portions 
respecti\-ely.  In  most  eases  a  good  li'iis  will  be  sullieieiit  to  di.sclose 
the  charaetc-rs,  but  when  insufficient,  recourse  must  be  had  to  the 
stage  and  low  power  of  a  comj^ound  mier()scoi)e.  Further  details  regard- 
ing this  process  will  be  found  in  our  chapter  devoted  especially  to  the 
methods  of  floral  dissection. 


76 


THE  GYNAECIUM 


First  Plan  of  Ovarian  Structure. — Two  distinct  plans  for  the  enclosure 
of  the  cavity  of  the  angiospermous  ovary  are  recognized.  In  the  first 
(Fig.  219)  the  margins  of  one  carpel  meet  each  other,  and  then,  by  more 
or  less  of  an  involution,  form  the  placenta  with  its  two  rows  of  ovules 
within  a  single  cell.  If  two  or  more  of  such  carpels  then  unite  in  one 
compound  ovary  (Figs.  221  and  222),  each  necessarily  forms  its  own 
cavity,  and  there  are  as  many  cells  as  such  a  pistil  has  carpels,  unless 
some  modification  of  structiu'e  shall  take  place,  as  illustrated  below. 

Axillary,  Axile,  or  Central  Placentae. — In  all  cases  where  closed  carpels 
of  this  sort  unite  in  a  compound  ovary,  their  ventral  sides  come  into 
contact,  and  the  placentae  are  brought  together  at  the  center  and  are 
known  as  Axillary,  Axile,  or  Central. 


Fig.  219.  Transverse  section  tlirough  1-celled  monocarpellary  ovary  of  bean.  220.  The  same, 
through  2-celled  monocarpellary  ovary  of  Astragalus.  221.  The  same,  through  upper  2-celled  portion 
of  dicarpellary  ovary  of  Datura.  223.  Through  lower,  4-chambered  portion.  222.  The  same,  through 
the  5-carpelled  and  5-celled  ovary  of  Vaccinium.  224.  Through  the  5-carpelled,  but  10-celled  ovary 
of  the  flax. 


Abortion  of  the  Septa. — If  the  septa  between  the  cells  now  become 
aborted  (Fig.  230),  the  placentae  are  left  free  in  the  center  and  are 
collectively  called  the  Free  Placenta. 

True  and  False  Septa  and  Cells. — ^The  walls  separating  the  cells  of 
ovaries  constructed  upon  this  first  plan,  because  they  consist  of  the 
original  carpellary  walls,  are  called  "True,"  as  are  the  cells.  When, 
as  sometimes  happens  (Fig.  220),  a-  new  septum  develops  from  the 
carpellary  midrib,  extending  across  to  the  placenta  and  separating  its 
two  rows  of  ovules  into  two  cells,  the  term  "False"  is  applied  both  to 
the  septum  and  to  the  cells  so  resulting.  If  there  be  several  carpels  to 
the  pistil,  and  each  undergoes  this  change,  it  is  clear  that  there  must 
result  twice  as  many  cells  as  there  are  carpels  (Figs.  223  and  224). 

Chambers. — When  septa  are  incomplete,  the  imperfectly  separated 
cells  which  result  are  called  Chambers,  and  the  ovary  is  said  to  be 
Chambered.  Thus  the  ovary  of  Datura  is  completely  2-celled  (Fig. 
221),  but  each  cell  is  2-chambered  by  partial  walls  which  exist  at  the 
basal  portion  only  (Fig.  223). 


BASAL  A^'D  APICAL  PLACENTAE 


77 


Second  Plan  of  Structure.— Quite  a  diflVrciit  group  of  appearances 
will  result  from  the  liiii^lier  or  more  comi)lex  form  of  carpel  union,  by 
which  the  ])roximate  margins  of  two  adjacent  carpels  meet  and  unite 
(Fig.  225)  instead  of  two  belonging  to  the  same  carpel.  The  result  of 
this  form  must  be  a  single  cavity  or  a  1-celled  .ovary,  without  regard 
to  the  number  of  carpels,  unless,  as  in  the  mustard  (Fig.  22(1),  one  or 
more  false  septa  may  divide  it. 

Axillary  Placentae. — It  has  been  observed  that  in  all  cases  of  the 
first  plan  of  ovarian  structure,  the  placentae  will  be  central.  It  is 
equally  clear  that  in  all  cases  of  the  second,  the  placentae  must  be 
formed  upon  the  sides,  where  the  edges  of  the  carpels  meet.  Such 
placentae  are  called  Parietal  (Figs.  225  to  229).  Such  placentae  may, 
by  an  extensive  involution  of  the  margins,  be  carried  very  nearly,  or 
quite,  to  the  axis  (Figs.  227  and  228),  but  unless  cohesion  actually 
occurs  at  that  p(Mnt  they  are  parietal  and  the  ovary  is  1-celled. 


;i>26 


230. 


Fig.  225.  The  2-carpeIled,  1-celled  ovary  of  the  gentian.  22G.  2-carpelled  and  falsely  2-celled  ovary 
of  mustard.  227.  A  2-carpeIled,  1-celled  ovary,  its  placentae  nearly  meeting  in  the  axis.  228  and  229. 
The  same,  3-carpclled.  230.  The  free  central  placenta  of  Primula.  231.  A  1-celled  ovary  with  basal 
placenta.  232.  2-carpclIed,  1-celIed  ovary  of  Ubolaria,  the  placentae  extended  to  completely  line  the 
wall. 


Modifications  of  the  Placenta. — Some  further  modifications  of  the 
placenta  require  our  consideration.  The  free  central  placenta  has 
been  considered.  Such  a  placenta  frequently  becomes  partly  aborted 
by  the  gradual  (lisai)])earaiice  of  its  upper  portion. 

Basal  and  Apical  Placentae. — Tliis  process  may  continue  until  the 
placenta  is  reduced  to  a  trace  at  the  base  (Fig.  231).  In  other  cases  it 
will  be  reduced  to  a  trace  at  the  apex  (Figs.  235  and  237).  Basal  or 
apical  placentae  may  be  Centric  or  Fccentric.  Modifications  of  these 
processes  may  result  in  restricting  the  placenta  to  any  intermediate 
point.  Upon  the  other  hand,  such  a  j)lacenta  may  become  enlarged  and 
fleshy.  Similar  changes  may  occur  in  the  j)arietal  placenta.  It  may 
become  reduced  to  a  mere  point  pre.ser\e(l  at  the  apex,  base,  or  inter- 
mediate portion.     In  the  watermelon  it  becomes  enormously  enlarged. 


78  THE  GYNAECIUM 

filling  the  entire  cavity  with  a  fleshy,  edible  mass.  In  the  Obolaria 
(Fig.  232)  it  is  laterally  expanded  to  form  a  more  or  less  complete  false 
lining  to  the  ovarian  cavity.  In  this  position  it  may  remain  free  or 
become  coherent,  so  that,  as  in  this  case,  the  entire  face  of  the  ovary 
may  appear  to  be  ovuliferous.  By  a  subsequent  obliteration  of  a  portion 
of  such  an  expanded  placenta,  the  remaining  portion  may  be  seen  to 
assume  an  abnormal  position,  being  occasionally  confined  to  the  midrib 
itself. 

Ovules. —  Xumbcr  of  Ovules. — As  has  already  been  pointed  out,  the 
number  of  ovules  is  extremely  variable  and  the  proportion  of  them  which 
become  fertilized  is  little  less  so. 

Position  of  Ovules. — The  position  of  the  ovules  is  to  a  great  extent 
determined  by  the  nature  of  the  placenta,  as  has  already  been  explained. 
It  calls  for  a  number  of  distinctive  terms.  The  two  rows  of  ovules 
produced  by  the  two  carpellary  margins  do  not  always  appear  distinct, 
but  may  be  reduced,  before  or  after  fertilization,  to  one. 

Series  of  Ovules. — A  vertical  row  of  ovules  is  called  a  series,  and  ovules 
are  thus  defined  as  being  One-serialled,  Two-serialled  (Fig.  219),  etc. 
When  there  are  many  series,  so  that  the  number  is  not  readily  made  out, 
we  simply  say  that  they  are  Many-serialled  (Fig.  227). 

Collateral  Ovules. — Ovules  placed  side  by  side  (Fig.  219)  are  called 
Collateral. 

Crowded  Ovules. — Sometimes  no  definite  series  can  be  made  out, 
owing  to  the  crowding  of  many  ovules  into  a  small  space,  as  in  Obolaria 
(Fig.  232).    They  are  then  said  to  be  Crowded. 

Divergence  of  Ovules. — Collateral  ovules,  and,  indeed,  any  ovules 
standing  together  and  deviating  from  a  straight  line,  have  a  tendency 
to  turn  their  foramina  away  from  one  another. 

Direction  of  Omdes. — As  to  the  directions,  in  relation  to  the  ovary, 
which  ovules  assume,  they  are  Erect  (Fig.  233)  when  standing  erect 
from  the  base;  Suspended  (Figs.  235  and  237)  when  occupying  an 
exactly  opposite  position ;  Horizontal  (Fig.  234)  when  taking  a  direction 
at  right  angles  to  the  axis  of  the  ovary;  Ascending  (Fig.  238)  when 
directed  obliquely  upward  from  some  point  intermediate  between  base 
and  apex;  and  Pendulous  (Fig.  239)  when  directed  obliquely  downward 
from  such  a  point.  When  starting  as  an  ascending  ovule  and  afterward 
drooping  (Fig.  236)  an  ovule  is  Resupinate,  or  when  as  in  Fig.  240, 
Recurved-pendulous. 

Obscuring  of  the  Position. — An  ovule  may  have  its  direction  obscured 
by  peculiarities  of  attachment.     Thus,  in  Loxoijterygium  (Fig.  178), 


STRUCrURE  AND  PARTS  OF   THE  OVULE  79 

the  real  base  becomes,  l)y  extreme  oblicjiiity,  ai)i)arently  lateral  and 
causes  an  erect  ovule  to  be  ai)i)arently  ascending.  That  of  Anemone 
is  suspended,  but  owing  to  the  same  condition  a|)])arently  only  jjcndu- 
lous.  The  terms  erect  and  suspended  are  after  all  only  relative,  as  we 
can  ne\'er  be  sure  that  an  ()\iile  wliich  a])pears  in  sucli  i)osition  is  really 
the  uppermost  or  lowermost  of  its  series.  \'(ry  often  others  which 
would  have  been  in  reality  the  basal  or  apical  lia\e  become  aborted, 
as  in  the  last  case  illustrated. 

A  merely  recurved  ovule  is  not  to  be  mistaken  for  an  anatropous 
ovule.  The  latter,  as  will  now  be  explained,  has  the  contiguous  portion 
of  the  funicle  adherent  as  a  raphe,  which  comes  away  with  the  seed 
at  maturit\'. 


Fig.  233.  Erect  ovule  of  Symmeria.  234.  Horizontal  ovule  of  Paullinia.  235.  Pendulous  ovule  of 
Guaiacum.  236.  Resupinate  ovule  of  Euonymus.  237.  Suspended  ovule  of  Drymicarpus.  238.  As- 
cending ovule  of  Euonymus.    239.  Pendulous  ovules.     240.   Recurved  pendulous  ovule  of  Drunnichia. 


Structure  and  Parts  of  the  Ovule.— The  recognized  varieties  of  ovules 
are  based  upon  cxtenial  structure,  which  will  here  be  briefly  considered. 
The  details  of  their  inner  structure  will  be  considered  in  our  cliajjter  on 
Fertilization. 

Body  and  /'/////Vv////.v.-  The  ovule  consists  of  a  Body  (Fig.  iMO,  a) 
and  a  Funiculus  or  Stem  (h).  Named  in  the  order  of  time  in  which  they 
are  develoi)ed,  the  i)arts  of  the  body  are  as  follows: 

Xucelln.s  and  Coals. — The  Nucelius,  or  central  i)ortion  (Figs.  241  to 
244,  /(),  containing  the  parts  essential  to  reproduction,  and  two  coats, 
the  Primine  or  inner  (/,•)  and  Secundine  or  outer  (.v).  Certain  i)arts  of 
these,  or  jjoints  upon  them,  also  have  distinctive  names. 

The  Mirropiile. — The  more  or  less  circular  opening  (///)  left  at  the 
apex  by  the  failure  of  the  coats  to  comi)lctcIy  inclose  the  nucclhis  is 
the  I'^oraincii. 


80 


THE  GYNAECIUM 


The  Chalaza. — The  structurally  opposite  end  of  the  body,  or  the 
point  where  nucellus,  coats,  and  apex  of  funiculus  separate  from  one 
another  (c),  is  the  Chalaza. 

The  Raphe. — If  the  body  become  inverted  upon  its  funiculus, 
either  partly  (Fig.  24.':))  or  wholly  (Fig.  242),  the  portion  of  the  funiculus 
against  which  it  lies  (r)  will  become  adnate  to  it,  and  is  known  as  the 
Raphe.  The  portion  of  the  funiculus  remaining  free  (/)  is  then  specific- 
ally known  as  the  funiculus.  When  hereafter  in  this  work  the  last 
term  is  used  it  will  be  understood  as  applying  to  this  free  portion.  It 
is  thus  seen  that  the  raphe  is  limited  at  its  distal  end  by  the  chalaza; 
but  separation  of  this  seed  at  maturity  cannot  take  place  at  this  point, 
owing  to  the  adnation  of  the  raphe,  as  it  would  do  if  no  such  adnation 
existed. 


Fig.  241.  Atropous  or  orthotropous  ovule;  /,  funiculus;  c,  chalaza;  n,  nucellus;  k,  primine;  s, 
secundine;  m,  micropyle;  em,  embryo-sac.  242.  Anatropous  ovule;  h,  hilum;  r,  raphe;  other  let- 
tering the  same.    243.  Amphitropous  ovule.    244.  Campylotropous  ovule. 


The  Hilum. — Separation  in  such  case  must  take  place  at  the  point 
where  raphe  and  funiculus  join;  hence  the  Hilum,  as  such  point  of 
separation  is  called,  may  be  variously  situated,  and  need  not  coincide 
with  the  chalaza.  In  Fig.  241  it  is  at  the  chalaza,  in  Fig.  242  at  the 
opposite  end  Qi),  while  in  Fig.  243  (li)  it  is  about  half-way  between. 
The  parts  here  enumerated  are  not  always  conspicuous  and  may  be 
easily  overlooked  by  the  beginner: 

Forms  of  Ovules. — The  nucellus  is  the  essential  part  of  the  ovule,  which 
in  some  cases  consists  of  nothing  else,  and  e\e\\  this  may  be  reduced  to 
its  lowest  es.sential  elements.  An  ovule  without  either  coat  is  Naked 
or  Achlamydeous;  with  only  primine  it  is  Monochlamydeous,  and  with 
both  it  is  Dichlamydeous.  An  ovule  without  funiculus,  and  the  same 
is  true  of  any  organ  not  borne  upon  a  stem,  is  Sessile.  The  form  of  the 
funiculus,  as  well  as  its  direction,  always  calls  for  inspection.  It  may 
be  very  short  and  broad  (Fig.  241),  or  elongated  and  slender  (Fig.  240), 
and  the  latter  form  may  be  either  straight  or  variously  curved. 


FORMS  OF  OVULES  81 

The  Anatropous  Ociilc. — An  anatropous  ovule  (Fig.  242)  is  one  tlie 
body  of  which  is  completely  inverted.  The  raphe  runs  its  entire  length 
and  the  micropyle  is  brought  close  to  the  hiluni,  while  the  chalaza  is 
at  the  opposite  end. 

TJw  Amphitropous  Oeule. — An  amphitro])ous  ()vule  (Fig.  243)  is  one 
which  is  i)artly  inverted,  occupying  a  position  more  or  less  at  right 
angles  with  its  funiculus.  Its  raphe  runs  only  part  of  its  length,  and  the 
hilum  is  at  some  point  intermediate  between  the  chalaza  and  micro- 
pyle, which  are  at  opposite  ends. 

The  CampyJotropom  Omde. — A  campylotropous  ovule  (Fig,  244) 
is  one  which  need  not  be  at  all  inverted,  but  the  body  of  which  is 
doubled  over  so  as  to  bring  the  micropyle  down  near  the  chalaza.  It 
has,  of  course,  no  raphe,  and  the  hilum  and  chalaza  are  one.  It  is  very 
difficult  to  distinguish  this  form  from  an  anatropous  ovule  with  a  very 
broad  raphe. 

The  Atropous  or  Orthotropoiis  Omde. — This  (Fig.  241)  is  an  ovule 
which  is  neither  doubled  nor  turned,  the  body  being  straight  and  erect 
upon  the  funiculus,  and  having  no  raphe,  the  hilum  and  chalaza  at 
one,  and  the  micropyle  at  the  opposite  end. 

Before  proceeding  to  the  subject  of  pollination  and  fertilization  and 
the  changes  in  the  several  parts  of  the  flower  consequent  thereon,  we 
must  consider  in  detail  the  torus  and  its  modifications. 


CHAPTER    VII 

THE  TORUS 

Review. — The  fundamental  principles  of  anthology  are  based  upon 
the  nature  of  the  torus  as  a  modified  branch.  We  have  already  con- 
sidered the  evidences  of  this  fact  depending  upon  its  position  and  the 
relative  positions  of  the  parts  developing  upon  it.  We  shall  now  con- 
sider some  which  depend  upon  its  modifications.  These  are  in  part 
permanent  and  typical  and  in  part  exceptional  and  abnormal. 

Elongation  of  the  Intemodes. — Among  the  latter  we  note  that  in  those 
frequent  cases  in  which  the  parts  of  flowers  revert  to  the  leaf  condition, 
the  torus  often  elongates,  separating  the  floral  series  exactly  as  whorls 
or  spirals  of  leaves  are  separated  by  the  internodes  upon  a  branch.  At 
other  times,  the  torus  will  be  continued  beyond  the  apex  or  center  of 
the  flower  in  the  form  of  a  leafy  branch.  Occasionally  one  of  the  sepals 
will  be  found  at  its  proper  radial  point,  but  vertically  distant  from  the 
rest  of  the  calyx,  a  portion  of  the  flower  stem  intervening. 

The  Anthophore. — A  similar  condition,  but  affecting  an  entire  series, 
normally  characterizes  certain  species,  or  groups  of  species.  The 
elongation  may  affect  any  internode  or  internodes.  When  (Fig.  246,  a) 
it  is  between  calyx  and  corolla  it  is  called  an  Anthophore.  Sometimes, 
as  in  Viscaria  (Fig.  248),  the  anthophore  may  be  very  slight,  so  as  to 
escape  detection  until  a  longitudinal  section  reveals  its  presence. 

The  Gonophore. — A  similar  elongated  portion  between  corolla  and 
androecium  is  a  Gonophore  (Fig.  249,  a). 

The  Gynophore. — One  between  androecium  and  gynoecium  (Fig.  249, 
b,  and  Fig.  252,  a)  is  a  Gynophore.  A  thecaphore  (Fig.  9)  often  resembles 
a  gynophore  and  may  be  mistaken  for  it.  The  point  of  articulation  and 
separation  at  maturity  will  determine  whether  the  stalk  is  a  portion  of 
the  ovary  (thecaphore)  or  of  the  torus  (gynophore) . 

The  Carpophore.— A  slender  extension  of  the  torus  upward  among  the 
carpels,  which  are  attached  to  it,  constitutes  the  Carpophore,  as  in 
Erodium  (Fig.  245).  The  presence  of  a  carpophore  is  characteristic  of 
plants  in  the  Umbelliferae  (P'ig.  247). 

The  Gynobase. — In  the  Boraginaceae  the  carpophore  is  frequently 
reduced  to  a  pyramidal  or  conical  form,  or  is  shortened  or  laterally 


/''O/i'il/.S  OF   THE   DISK 


83 


expanded  until  il  is  iiicrcly  convex  or  even  ])l;me.  To  all  such  modi- 
fications the  term  (lyiiohasc  is  ajjplicd.  Jn  this  con(htion  it  may 
become  liollowed  ont  at  the  insertion  of  the  carpels,  as  in  borage  (Fig. 
250).  In  all  forms  of  the  gynol)ase  it  is  important  to  note  the  point 
of  attachment  of  the  divisions  of  the  ovary  and  the  scars  wliich  the 
latter  lea\e  upon  removal. 


Fig.  245.  Pistils  of  Erorliiim  siiriiifziiiK  away  from  the  carpopliore  (a).  24(5.  l-'lower  of  Lychnis, 
showing  anthophore  at  a.  247.  Carpels  of  parsnip  attached  at  summit  of  carpophore.  248.  Flower  of 
Viscaria  with  obscure  anthophore.  249.  Flower  of  Maerna,  a  gonophore  at  a,  a  gynophorc  at  h. 
250.  Gynobase  of  Borago.  251.  Numerous  pistils  of  Magnolia,  imbricated  upon  a  carpophore.  252. 
Greatly  enlarged  gynophore  of  Xelumbium.  253.  Ring-shaped  disk  (a)  of  Halpichroa  adnate  to  calyx. 
254.  Epigynous  disk  (a)  of  Coussarea. 


Abbreviation  of  the  Internodes. — The  al)o\e  considerations  refer  to 
elongations  of  internodes  of  the  torus.  The  condition  of  adnation  of 
floral  parts  may,  upon  the  other  hand,  be  usually  looked  upon  as  one 
in  which  the  normally  very  short  internodes  of  the  torus  are  still  further 
shortened,  so  as  to  bring  the  parts  into  most  intimate  connection. 

Lateral  Expansion  of  the  Internodes.-  lii>tca(l  of  nudcrgoing  a  uumt 
elongation  of  its  internodes,  the  torus  may  l)c  latcrall>-  exi)anded  at  any 
or  all  points,  with  or  without  elongation,  and  in  imuiincrable  forms. 

The  Disk. — An  exi)ansion  or  appendage  of  this  kind,  although  the 
term  may  be  properly  regarded  as  including  all  forms  of  enlargement 
or  extension  of  the  torus,  is  called  a  Disk. 

Forms  of  the  Disk. — The  sim])lest  form  is,  ])crliaps,  that  seen  in  the 
blackberry,  a  hemisphere,  with  the  j)istils  arranged   ui)on  its  surface 


84 


THE  TORUS 


(Fig.  305),  although  most  of  the  enlargement  here  seen,  as  in  the  next, 
is  the  accrescence  of  fructification.  The  disk  of  the  strawberry  (Fig. 
304)  is  similar,  but  its  pistils  are  partly  immersed.  In  the  rose,  a 
related  plant  (Figs.  59  and  GO),  the  form  is  modified  by  the  elevation  of 
the  margins,  instead  of  the  center,  so  that  a  cup-shaped  disk  is  formed, 
the  pistils  attached  over  its  inner  surface.  In  the  cherry  (Fig.  58)  the 
disk  is  thin  and  lines  the  calyx-tube,  the  pistil  being  free.  In  the  apple 
there  is  a  similar  disk  lining  the  calyx-tube,  and  it,  at  maturity,  is 
thick,  fleshy,  and  edible,  and  encloses  the  five  pistils.  In  the  Magnolia 
(Fig.  251)  the  torus  is  vertically  much  elongated  and  at  the  same  time 


Fig.  260.  Saucer-shaped  disk  of  Pseudima.  261.  Similar  disk  of  Allophyhts,  but  irregular  and  uni- 
lateral. 262.  Disk  with  two  lobes  coherent.  263.  Cupulate,  sinuate-margined  disk  of  Hippocratea. 
264.  Disk  of  Xanthoceras,  of  five  distinct  horns.  265.  Cupulate  disk  with  lobed  margin.  266. 
Campanulate  disk  of  Santalum,  adnata  to  calyx-tube. 


much  thickened,  the  pistils  adnate  along  its  surface.  In  the  Nelumbo, 
the  torus  (Fig.  252)  is  enlarged  into  a  top-shaped  or  Turbinate  body, 
with  the  pistils  embedded  in  the  flat  upper  surface.  Instead  of  thus 
occupying  a  hj-pogynous  position,  the  disk  may  be  projected  between 
any  two  of  the  circles,  and  it  may  be  wholly  or  partly  adnate  to  either 
(Fig.  266,  a),  or  to  both  of  them,  or  it  may  be  entirely  free.  When 
adnate  to  both  circles  it  is  plain  that  it  becomes  responsible  for  the 
existing  adnation  between  the  latter.  It  may  then  exist  only  at  the 
base,  or  it  may  entirely  fill  up  the  interspace  between  the  parts  and  even 
become  epigynous,  so  that  the  ovary  is  immersed  in  it  or  buried  under- 
neath it  (Fig.  254,  a) .    The  adnate  disk  may  be  shorter  or  longer  than 


FORMS  OF  THE  DISK  85 

the  circle  to  wliidi  it  is  adnate.  The  simplest  manifestation  of  tlie  disk 
is  that  of  a  mere  swelling  or  ring  (Fig.  200)  at  the  summit  of  the  torus; 
its  greatest  that  in  which  it  becomes  an  elongated  cu])  or  tube.  Either 
form  may  be  entire  or  more  or  less  divided,  from  that  Avith  a  mere  sinu- 
ately  lobed  margin  (Fig.  263)  through  the  toothed  and  lobed  (Fig.  2G5) 
to  that  consisting  of  entirely  separate  divisions  (Fig.  204).  It  may  be 
regular,  as  in  the  above  illustrations,  or  very  irregular  (Fig.  2()1),  and 
cohesion  may  exist  between  some  of  its  divisions  while  the  others  are 
distinct  (Fig.  262).  The  lower  portion  may  be  adherent  while  the 
upper,  lobed  or  entire,  is  free  (Fig.  260).  It  may  be  itself  appendaged, 
and  it  may  or  may  not  be  glandular  in  nature.  Finally,  we  note  that 
the  disk  may  be  double,  its  two  circles  occupying  different  internodes 
of  the  torus.  The  texture  of  the  disk  is  commonly  thicker  than  that 
of  the  other  parts,  but  it  may  be  laminar.  It  is,  therefore,  sometimes 
easy  to  mistake  a  disk  for  a  corolla,  aborted  stamen-circle,  or  crown. 
In  all  its  peculiarities  above  described,  and  in  the  number,  size,  and  form 
of  its  divisions  and  appendages,  the  disk  is  characteristic  and  of  the 
greatest  value  in  classification,  either  generic,  as  in  the  Gesneriaceae,  or 
specific,  as  in  Eschscholtzia. 


CHAPTEPv    VIII 

DISSECTION  AND  ANALYSIS   OF  THE  FLOWER 

Apparatus  Required;  Microscopes. — For  the  thorough  and  convenient 
examination  of  floral  structure,  it  is  desirable  to  employ  both  the 
compound  and  the  simple  microscope,  and  it  is  better  to  use  two  forms 
of  the  latter.  The  compound  microscope  for  ordinary  use  should  have 
a  focus  of  about  li  inches,  and  it  should  be  provided  with  a  strong 
illumination  for  viewing  opaque  objects.  The  simple  microscopes  used 
should  be  a  dissecting  microscope,  having  a  magnifying  power  of 
some  20  to  30  diameters  and  an  ordinary  jeweller's  loup.  It  must  not 
be  assumed,  however,  that  all  of  these  instruments,  useful  as  they  are, 
are  essential  to  the  work.  Excellent  work  in  all  directions  can  be 
performed  by  the  use  of  a  strong  loup  alone,  especially  if  it  be  held  in 
the  eye  or  attached  by  means  of  a  flat  steel  wire  passing  around  the 
head  or  inserted  into  a  spectacle  frame,  so  that  both  hands  may  be 
free  for  the  work  of  dissection. 

Other  Apparatus. — ^The  other  apparatus  required  is  a  pair  of  pointed 
forceps,  a  pair  of  stout  needles  inserted  into  thick  wooden  handles,  and 
a  dissecting  knife. 

Regular  Order  of  Procedure. — ^It  is  well  for  the  student  in  the  examina- 
tion of  flowers  to  accustom  himself  to  a  definite  order  of  procedure,  as 
the  numerous  points  to  be  noted  are  thus  far  less  likely  to  be  forgotten 
or  overlooked  than  when  considered  in  a  disorderly  manner.  It  is 
furthermore  highly  desirable  that  the  characters  observed  should  be 
written  down  in  systematic  sequence  before  the  book  is  referred  to. 
The  order  of  procedure  is  from  without  inward,  or  in  other  words,  from 
below  upward.  The  anthotaxy  should  first  be  carefully  examined  and 
the  position  of  the  flower  with  reference  to  others  in  the  cluster  noted, 
as  well  as  its  position  upon  the  stem  and  the  direction  in  which  it  faces. 
The  position  when  in  l)ud  should  be  compared  with  that  when  in  flower. 
When  flowers  are  aggregated  in  ,close  clusters  surrounded  by  involucres, 
all  the  characters  of  the  latter  as  a  whole  and  of  the  bracts  of  which 
they  are  composed,  must  be  noted  precisely  the  same  as  though  we  were 
studying  the  calyx  of  a  single  flower.  The  receptacle  upon  which  the 
flowers  are  borne  within  the  involucre  must  also  be  thoroughly  examined 
as  to  its  size,  form,  and  surface  and  the  ])resence  of  bracts  or  scales 
interposed  among  the  flowers. 


liFJUl.Mi  OUDKU  OF   /'!,•( K •!■: I )Uh-J'J  87 

("oiniii.u'  next  to  the  study  of  ;i  single  flower,  it  iiiii.st  first  he  cxaiuiiicd 
in  the  hud  coiuhtioii  and  its  ])r;K'floration  dctcnniiuvh  In  inakini,' 
this  ohservation,  it  is  necessary  that  the  ])arts,  first  of  the  calyx  and 
afterward  of  the  corolla,  should  one  \)y  one  he  carefully  separated  with 
needle  or  forcei)s,  heginninfj;  at  the  apex  and  drawing  backward  and 
downward,  the  lines  of  separation  being  closely  scrutinized  while  the 
separation  is  taking  place.  The  fully  expanded  flower  is  next  examined. 
The  presence  of  both  calyx  and  corolla,  or  of  one  or  neither,  is  first  in 
order,  'i'lie  regularity  or  irregularity  of  the  several  circles  can  be 
determined  at  a  glance,  as  well  as  their  numerical  symmetry.  The 
same  ra])id  glance  will  determine  the  relative  sizes  of  the  different 
circles,  the  exsertion  or  inclusion  of  the  essential  organs,  the  general 
form  of  the  flower,  and  color,  surface,  and  positions  of  the  parts.  All 
the  above  observations  may  be  regarded  as  superficial.  It  then  becomes 
necessary  to  examine  into  those  details  which  require  dissection. 

The  sepals  should  first  be  turned  back  and  examined  as  to  their 
cohesion  at  the  base,  when  this  is  so  slight  as  to  be  inappreciable  upon 
superficial  examination.  At  the  same  time  their  adhesion  to  the  inner 
series,  especially  to  the  ovary,  can  usually  be  determined.  The  corolla 
should  then  be  carefully  pulled  oft'  to  ascertain  whether  any  degree  of 
cohesion  exists  among  its  petals  and  also  to  determine  the  relation  of  the 
stamensto  it.  Thestamens  are  next  to  be  removed,  and  this  is  preferably- 
done  by  pushing  against  them  at  the  base  from  a  lateral  direction  with 
a  blunt  instrument,  so  as  to  ascertain  whether  they  exhibit  a  tendency 
to  cohere  in  groups.  The  superficial  characters  of  the  g>'naecium  also 
can  now  be  readily  ascertained.  The  presence  of  a  disk  interposed 
between  gynaecium  and  calyx  must  then  be  searched  for  and  its  char- 
acters determined,  as  in  the  case  of  the  other  circles.  It  has  already 
been  explained  that  the  disk  may  be  easily  overlooked  through  its 
adhesion  to  calyx  or  corolla  or  both.  Occasionally  it  will  be  overlooked 
because  it  exists  in  the  form  of  a  granular  or  powdery  mass. 

The  general  observations  thus  determined  should  next  be  verified 
and  more  accurately  made  by  making  a  vertical  incision  through  one 
side  of  the  calyx  and  disk,  if  the  latter  be  i)resent,  and  carefully  remov- 
ing them.  The  body  thus  renio\-e(l  may  then  be  flattened  out  and  the 
relations  of  all  its  parts  be  fully  seen.  If,  after  the  initial  incision  has 
been  made,  it  be  ascertained  that  adhesion  exists  l)etween  the  calyx 
and  gynaecium,  so  that  the  former  is  not  readily  removed,  the  incision 
nmst  then  be  carried  entirely  through  the  flower  and  the  latter  sei)a rated 
into  two  a|)proximately  e(|ual  portions.  In  either  case  search  for 
nectaries  or  other  ai)penilages  nnist  next  \)v  made.     This  subject  has 


88  DISSECTION  AND  ANALYSIS  OF  THE  FLOWER 

been  so  thoroughly  considered,  that  it  need  not  be  again  taken  up  except 
to  say  that  glands,  which  are  frequently  metamorphosed  stamens  or 
appendages  to  the  several  parts,  must  not  be  mistaken  for  a  disk.  With 
the  flower  in  this  position  it  may  also  easily  be  seen  whether  the  parts 
are  cyclical,  and  if  so  the  number  of  circles  may  be  determined.  If 
duplication  has  occurred,  its  origin  in  chorisis  or  metamorphosis  is 
readily  determined,  while  if  sujipression  has  occurred  it  can  readily 
be  referred  to  the  respective  circle. 

The  relation  of  the  parts  to  one  another  having  been  thus  determined, 
each  of  them  must  next  be  studied  individually.  The  shape  and  texture, 
and  the  division  into  parts,  with  the  details  of  any  existing  appendages, 
will  be  sought  separately  in  sepal,  petal,  and  stamen  and  in  filament 
and  anther  separately.  In  the  examination  of  the  stamen,  it  is  essen- 
tial that  it  be  examined  separately  in  direct  lateral,  ventral,  and  dorsal 
views,  as  only  thus  can  the  true  relations  of  its  parts  become  known. 
The  form  of  attachment  of  anther  to  filament  and  the  point  of  junction 
between  filament  and  connective  are  next  in  order,  as  well  as  the  form 
of  dehiscence  of  the  thecae  and  especially  the  position  and  direction 
assumed  by  the  sutures,  pores,  or  valves  of  the  latter.  The  chief  diffi- 
culty in  the  examination  of  the  stamens  will  be  in  determining  the  part 
upon  which  any  existing  appendages  originate.  The  position  which 
such  an  appendage  occupies  is  frequently  quite  misleading  as  to  the 
nature  of  its  origin,  and  it  must  be  carefully  moved  about  with  the 
points  of  the  needles,  great  care  being  taken  that  no  delicate  attachment 
is  severed,  before  it  can  be  definitely  ascertained  whether  an  appendage 
originates  from  filament,  connective,  or  theca. 

It  is,  moreover,  not  rarely  the  case  that  the  characters  of  appendage 
and  anther  are  so  concealed  or  even  substituted  that  the  one  may  be 
mistaken  for  the  other.  The  examination  of  the  stamen  is  not  com- 
plete until  the  characters  of  the  pollen,  as  to  its  being  granular  or 
collected  into  pollinia,  the  nature  and  characters  of  the  latter,  and  even 
the  characteristics  of  the  individual  pollen-grain,  have  been  determined 
by  the  aid,  chiefly,  of  the  compound  microscope. 

The  gynaecium,  still  in  position  upon  the  torus,  must  next  be  studied 
as  to  its  relations  to  the  latter  and  its  composition  of  united  carpels 
or  separate  pistils.  If  of  separate  pistils,  they  must  be  separately 
removed  from  the  torus,  great  care  being  taken  not  to  mutilate  the 
latter,  and  their  number  and  regularity  must  be  determined.  If 
regular,  the  detailed  examination  of  one  of  them  is  sufficient,  but  if 
irregular,  one  of  each  form  must  be  separately  studied. 

The  external  characters  of  the  pistil  present  no  difficulty  for  exami- 


PREPARATION  OF  DRIED  SPECIMENS  FOR  EXAMINATION     89 

nation,  bnt  the  examination  of  their  strueture  and  contents  constitutes 
perhaps  the  most  (hfHeult  i)art  of  floral  dissection.  It  is  very  desirable 
that  the  stigmas  be  subjected  to  examination  with  the  compound 
microscope,  as  the  character  of  its  surface  and  the  form  and  distril)ution 
of  the  stigmatic  surface  proper  upon  the  style  and  u]nm  the  body, 
which  may  at  first  sight  be  regarded  as  the  stigma,  is  frequently  a  matter 
of  the  utmost  importance.  The  dissecting  knife  must  now  be  used  for 
dividing  the  ovary  into  a  number  of  transverse  sections,  which  must 
then  be  separately  viewed  by  transmitted  light.  This  examination  will 
determine  the  number  of  cells  and  their  completion  by  the  continuation 
of  the  septa  from  top  to  bottom.  It  will  also  in  most  cases  be  sufficient 
to  enable  us  to  determine  the  number  of  ovules  and  the  position  and 
character  of  the  placentae.  All  these  points  should,  however,  be  veri- 
fied by  the  subsequent  examination  of  vertical  or  longitudinal  sections. 
Finally  the  ovules  must  be  removed  and  their  form  and  structure 
determined  by  the  aid  of  a  compound  microscope. 

It  may  be  pointed  out  in  conclusion  that  the  examination  of  a  single 
flower  is  not  always  sufficient  to  determine  the  structural  characters. 
Dimorphism  or  dichogamy,  unrecognized  by  the  student,  may  lead  to 
the  most  false  conclusions. 

The  student  should  also  be  cautioned  against  the  temptation  to 
examine  the  partially  or  wholly  matured  fruit  with  the  idea  that  he 
can  thus  more  easily  determine  the  characters  of  the  gynaecium.  As 
will  be  shown  later,  great  changes  frequently  occur  in  the  structure 
of  the  pistil  during  fructification. 

Preparation  of  Dried  Specimens  for  Examination.— The  oi-dcr  of  exam- 
ination is  the  same  whether  a  fresh  or  a  dried  flower  be  under  considera- 
tion. In  the  case  of  the  latter,  however,  it  is  necessary  that  it  be  first 
thoroughly  softened  by  immersion  in  water.  For  this  purj)ose  it  may 
be  left  in  warm  water  all  night  or  for  a  longer  period,  or  as  is  usually 
more  convenient,  it  may  be  boiled  for  from  one  to  five  minutes,  accord- 
ing to  its  texture,  in  a  s])oon  or  porcelain  dish  held  in  the  flame  of  an 
alcohol  lamj).  Considerable  exi)erience  is  required  to  know  just  how 
long  to  subject  it  to  the  action  of  the  hot  water.  If  too  quickly  removed, 
the  tissues  will  be  found  stifi"  and  resistant,  while  if  it  be  boiled  too 
long,  they  will  become  so  thoronulily  linij)  as  to  lose  all  trace  of  their 
natural  i)()siti<)n.  If  the  jmxcss  i>  jx  rfcctl^-  ])(M-formed,  the  flower  may 
be  thrown  \i\)(n\  a  blotter  and  after  the  excess  of  moisture  has  been  thus 
removed,  will  be  found  very  much  in  the  original  growing  condition 
and  yielding  easily  to  manipulation. 


CHAPTER    IX 

POLLINATION  AND  FERTILIZATION 

Review. — It  has  been  stated  that  the  essential  female  element  of 
reproduction  in  the  flower  is  produced  in  the  nucellus  of  the  ovule,  the 
male  by  the  germination  of  the  pollen-grain.  It  has  also  been  shown 
that  these  two  elements  are  produced  separately,  and  in  most  cases 
remotely,  from  one  another,  and  that  some  means  must  exist  for  bring- 
ing them  together  in  order  that  fertilization  may  be  effected. 

POLLINATION 

In  those  plants  (Gymnosperms,  P^igs.  174  and  175)  in  which  no 
stigma  exists,  this  is  accomplished  by  immediate  contact  of  the  pollen 
with  the  ovule,  which  is  exposed  for  the  purpose.  In  those  in  which  a 
stigma  exists,  it  is  accomplished  by  the  deposit  and  fixation  of  the 
pollen  thereupon.  To  either  of  these  processes  the  term  Pollination 
is  applied. 

Close-pollination  and  Cross-pollination. — The  two  elements  may 
proceed  from  the  same  flower,  in  which  case  the  term  Self-pollination  or 
Close-pollination  is  applied,  or  they  may  proceed  from  different  flowers, 
in  which  case  the  term  Cross-pollination  is  applied.  It  will  be  noted 
further  that  there  are  degrees  of  crossrpollination,  according  to  whether 
the  elements  proceed  from  flowers  upon  the  same  or  upon  different 
plants.  When  the  flowers  are  perfect,  it  is  at  least  possible  in  most 
cases  for  them  to  be  either  close-  or  cross-pollinated. 

Cross-pollination  Beneficial. — In  nearly  all  cases,  the  reproductive 
function  is  strengthened  through  cross-pollination,  which  explains 
the  fact  that  nearly  all  flowers  are  constructed  so  as  to  facilitate  the 
process,  while  most  of  them  are  so  constructed  as  to  incommode,  and 
very  many  to  prevent,  close-pollination.  In  a  few  cases  the  flower  is 
constructed  so  as  to  prevent  cross-pollination. 

Methods  of  Securing  Cross-pollination.-  I'lie  methods  of  effecting 
cross-pollination  may  be  divided  into  the  ordinary  and  the  exceptional. 


l'h'()\ISI(>.\S   FOR   ATTUACTIXa   IXSECTS 


!)1 


The  latter  must  he  considered  iii(hvi(hiall\ .  The  former  are  two — 
namely,  throufijh  the  agency  of  tlie  wind  and  throufj;h  that  of  insects 
(or  occasionally  other  animals). 

Anemophilous  and  Entomophilous  Flowers. — Flowers  adapted  to  the 
former  methods  are  called  Anemophilous;  those  adapted  to  the  latter 
are  called  Entomo])hilous.  Occasionally  the  flower  is  so  formed  that 
the  movement  of  the  water  during  rains,  or  in  streams,  effects  pollina- 
tion. 

Provisions  in  Anemophilous  Flowers. — The  activity  of  the  wind  hcing 
heyond  the  control  of  the  flower,  the  adai)tati()n  of  the  structure  of  an 
anemophilous  flower  is  limited  to  securing  the  benefits  of  such  action 
when  it  comes  into  play.  This  consists  chiefly  in  (1)  a  gregarious  habit 
— the  growing  together  in  great  numbers  of  individuals  of  one  kind,  as  in 
the  case  of  grasses  and  of  most  of  the  forest  trees  of  temperate  latitudes; 
(2)  a  very  abundant  j)()llcn  ('.]),  which  is  loosely  fixed,  one  method 
being  illustrated  by  Fig.  2()7,  light  and  easily 
removed  and  transported;  and  (4)  the  dispo- 
sition of  the  ovule  of  gymnos])erms,  and  the 
form  and  disposition  of  the  stigma  and  con- 
nected parts  of  angiosperms,  so  as  to  catch 
the  pollen.  All  these  provisions  may  be 
readily  seen  to  affect  the  process  in  the  case 
of  Pitiiift  pal  list  r  is,  for  example.  In  this 
l)laiit  the  ])()llcn-grains  contain  several  cells, 
all  but  one  of  them  empty,  thus  decreasing 

tlicir  specific  gravity.  They  are  produced  in  such  great  abun- 
dance that  the  crop,  carried  by  strong  winds,  has  been  known  to 
fall  at  a  great  distance  as  a  thick  deposit,  the  so-called  "sulphur- 
showers"  of  history.  The  trees  are  densely  massed,  to  the  exclusion 
of  almost  all  others,  and  bear  innumerable  cones  (Fig.  .SfiO),  each 
consisting  of  numerous  scales,  outwardly  flaring,  and  so  (lisi)ose<l  as 
to  catch  many  of  the  j)ollen  grains  and  guide  them  downward  to  the 
little  pockets  at  their  bases. 

Provisions  in  Entomophilous  Flowers.  In  entonioi)hilous  (lowers,  such 
provisions  as  aboNc  described  for  the  utilization  of  the  i)()llen-carr\ing 
forces,  nuist  be  preceded  by  others  of  a  dilVereiit  nature,  eal(ulate(j  to 
first  set  in  motion  and  attract  these  forces. 

Provisions  for  Attracting  Insects.  l*i-()\isi(»Ms  for  atti-acting  external 
agents  are  found  chiefly  in  the  form,  coloration,  and  size  of  the  Hower 
or  of  one  or  more  of  its  i)arts,  the  ])roduction  of  fragrant  and  nutritive 


Fig.  2()7 


Anemophilous  flower  of 
a  grass. 


92 


POLLINATION  AND  FERTILIZATION 


secretions  and  the  exercise  of  these  influences  at  the  most  opportune 
times. 

Form. — The  form  of  the  flower  is  efficient  when  it  resembles  a  form 
attractive  to  an  insect  the  visit  of  which  is  desirable,  or  when  it  is 
one  well  calculated  to  display  effectively  the  coloration;  and  it  is  not 
impossible  that  certain  forms,  like  certain  colors,  are  attractive  jmv  se. 
The  forms  of  nectar-bearing  flowers  are,  moreover,  in  most  cases,  such 
as  to  facilitate  the  collection  of  the  food  by  the  visiting  insect,  or, 
when  otherwise,  to  eft'ect  special  objects  to  be  considered  farther  on. 
For  example,  it  is  usually  a  peripheral  or  central  position  of  the  nectaries 

which  respectively  determine  the  ex- 
trorse  or  introrse  dehiscence  of  the 
anthers. 

Color.  —  Coloration  also  may  be 
attractive,  through  its  simulation  of 
an  insect  or  merely  by  its  serving 
to  make  known  to  the  insect  the 
presence  or  position  of  the  flower 
concerned — as  a  white,  light-colored, 
or  lustrous  flower,  in  attracting  in- 
sects which  fly  only  when  there  is 
little  light. 

Function  of  Neutral  Floivers.— 
Flowers  are  frequently  modified  in 
size  so  as  to  effect  these  results,  and 
this  modification  is  often  secured  at  the  expense  of  their  own  sexual 
functions.  Fig.  268  illustrates  a  cluster  of  Viburmnn  flowers,  the 
marginal  being  large  and  light-colored  and  admirably  adapted  to 
attract  insects,  but  destitute  of  perfect  reproductive  parts.  This 
tendency  to  produce  upon  the  same  plant  flowers  of  two  kinds,  the 
one  for  display,  the  other  for  rei)roduction,  is  widely  manifested.  In 
the  Einphegus,  the  flowers  produced  respectively  upon  the  lower  and 
upper  portions  of  the  stem  exhibit  this  difference.  In  such  heads  of 
flowers  as  the  Daisy,  the  showy  marginal  flowers  are  very  frequently 
sterile,  even  though  pistillate,  and  attract  insects  which  then  poIHnate 
the  inconspicuous  central  flowers. 

Odor. — The  odors  of  flowers,  while  frequently  offensive  to  the  human 
sense,  are  supposed  to  be  attractive  in  most  cases  to  the  insects  whose 
visits  favor  their  pollination.  They  result  from  the  evaporation  of 
volatile  oils.    The  glands  by  which  these  oils  are  excreted  and  in  which 


Fig.  208.  Inflorescence  of  Viburnum  with 
neutral  marginal  flowers. 


POLLINATION  BY  BIRDS  93 

they  are  stored  may  be  distributed  through  the  tissues  of  all  or  certain 
of  the  floral  parts,  or  their  presence  may  be  restricted  to  the  special 
appendages  described  below. 

Nectar  and  Nectaries. — The  nutritive  substances  other  than  pollen 
to  be  consumed  by  tlio  visiting  insect,  known  as  Nectars,  are  produced 
by  certain  special  glands  and  are  stored  in  or  upon  contiguous  receptacles 
called  Nectaries.  The  presence  of  these  nectaries  is  commonly  responsi- 
ble for  the  outgrowth  of  the  appendages  to  which  they  are  often  attached 
(Figs.  G3  and  05).  At  other  times  a  part  of  the  flower  not  conspicuously 
modified  produces  and  holds  the  nectar. 

Time  of  Activity. — The  influences  here  described  are  in  almost  all 
cases  exerted  at  certain  times  which  are  especially  favorable  for  securing 
the  desired  results.  In  speaking  of  the  perigone,  it  has  been  shown 
that  the  duration  of  flowers  varies  greatly.  It  may  be  further  stated 
that  those  which  perish  quickly  mature  and  ex])and  at  the  particular 
time  of  day  when  pollination  is  most  likely  to  occur.  Those  which  last 
for  several  days  enjoy  a  daily  resting  period  and  another  period  of 
greatest  activity,  the  details  of  which  vary  in  different  species  or  classes. 
Commonly,  the  perigone  becomes  more  or  less  folded  or  closed  during 
this  resting  period,  its  form  and  coloration  less  conspicuous,  the  exhala- 
tion of  odors  entirely  suspended  or  greatly  restricted,  and  access  to  the 
nectar  prevented  altogether.  At  the  same  time  that  its  functions  are 
thus  inactive,  its  position  is  such  as  to  afford  it  protection  of  various 
kinds  from  dangers  which  are  especially  imminent  during  the  hours  in 
which  it  rests. 

Sleep  of  the  Flower. — This  condition  of  inactivity  or  rest  is  commonly 
spoken  of  as  the  sleep  of  the  flower.  It  occurs  at  such  a  period  of  the 
day  as  finds  the  agencies  specially  adapted  to  pollination  in  its  case 
themselves  enjoying  their  rest.  As  these  again  become  active,  the 
flower  "awakens"  and  all  the  conditions  above  noted  are  reversed,  or 
at  least  such  of  them  as  affect  the  flower  in  question.  # 

Diurnal  and  Nocturnal  Flowers. — Flowers  in  which  this  active  period 
occurs  during  the  day,  whether  they  endure  for  but  one  day  or  longer, 
are  called  Diurnal;  those  in  which  it  occurs  at  night  are  called  Nocturnal. 
Besides  the  regular  daily  resting  period,  a  great  many  flowers,  by  virtue 
of  special  sensitiveness,  possess  the  power  of  assuming  such  a  condition 
on  special  occasions  when  the  conditions  call  for  it. 

Pollination  by  Birds. — Humming-birds,  as  well  as  insects,  are  active 
participators  in  the  operations  above  recorded.  Their  operations 
in  promoting  cross-pollination  in  the  Cinchona  group  have  been  largely 


94  POLLINATION  AND  FERTILIZATION 

responsible  for  some  of  the  most  far-reaching  economic  conditions  and 
results  in  the  history  of  the  drug  trade.  In  exceptional  instances,  still 
other  animals  take  ])art  in  this  work. 

Participation  by  other  Parts  than  the  Flower.^ — It  may  be  remarked  in 
passing  that  these  characters,  like  some  of  those  which  follow,  are  not 
restricted  to  the  flower  itself.  Very  frequently  other  portions  of  the 
plant  adjacent  to  the  flower  will  be  expanded,  brightly  colored,  and 
developed  into  special  forms,  while  the  odor  of  some  flowers,  due  to 
the  presence  of  glandular  tissues,  is  shared  by  the  foliage  and  other 
herbaceous  portions,  as  in  the  lavender.  Well-formed,  large  glands  are 
present  in  the  axils  of  the  primary  veins  of  the  leaves  of  some  species 
of  Cinchona,  although  the  precise  function  which  they  perform  is  by 
no  means  clearly  established. 

Provisions  for  Utilizing  Insect-visits. — The  special  contri^'ances  for 
utilizing  insect-visits  in  eft'ecting  pollination  are  far  more  elaborate 
and  varied  than  those  for  inducing  them,  which  we  have  already 
considered,  and  our  consideration  of  them  cannot  be  extended  beyond 
what  is  necessary  to  indicate  their  general  nature  and  classification, 
and  to  serve  as  a  key  in  understanding  the  complicated  modifications 
which  we  have  observed  the  typical  flower  to  undergo.  Usually  the 
effects  extend  in  two  directions — (a)  toward  excluding  the  pollen  from 
access  to  the  stigma  of  its  own  flower,  and  (6)  toward  securing  its 
access  to  that  of  another. 

Dichogamy. — One  of  the  most  frequent  methods  of  securing  the 
former  result  is  the  maturing  of  the  androecium  and  gynaecium  at 
different  times.    This  method  is  called  Dichogamy. 

Proterogyny  and  Proterandry.^ — By  it  the  ovules  of  a  flower  are  already 
fertilized  before  the  mature  pollen  of  that  flower  escapes  from  its  thecae 
(Proterogyny),  or  else  the  pollen  is  matured  and  utilized  before  the 
stigmas  of  that  flower  are  prepared  for  its  reception  (Proterandry). 

Proterandry  is  well  illustrated  by  Figs.  269  and  270.  The  former 
illustrates  the  anthers  erect  with  their  pollen  ready  for  removal,  while 
the  stigmas  are  yet  immature.  The  visit  of  an  insect  to  such  a  flower 
cannot  aft'ect  the  stigma,  but  will  result  in  the  transportation  of  the 
pollen  to  another  flower,  perhaps  in  the  condition  represented  by  Fig. 
270.  Here  it  will  be  received  upon  an  active  stigma,  the  anthers  having 
already  perished  and  dropped  beneath  the  margin  of  the  corolla. 

Figs.  271  and  272  illustrate  proterandry  assisted  by  a  special  mechan- 
ical device.  The  former  represents  a  flower  with  closely  syngenesious 
and  introrselv  dehiscent  anthers. 


PROrEIiOaYNY  AND  PROTERAXDRY 


95 


Its  style  is  two-cleft,  the  stigmas  existing  iipou  the  inner  faces  of  the 
branches,  their  outer  faces  being  clothed  with  stifi"  hairs  pointing 
nj)w;ir(l.  It  is  obvious  that  until  these  style-branches  separate,  polli- 
nation cannot  take  place.  Before  such  separation  occurs,  the  tip  of  the 
style  is,  by  elongation,  slowly  forced  u])  through  the  tube  of  the  anthers. 
The  anthers,  with  their  contained  pollen,  are  mature,  and  the  pollen  is, 
by  the  stifi'  hairs  upon  the  backs  of  the  style-branches,  torn  out  from 
its  receptacles  and  exposed  to  such  agencies  of  trans])()rtation  as  may 
be  prepared  to  act  upon  it.  Cases  are  even  known  in  which  the  tearing 
out  of  the  ])()l]cn   in  tliis  way  is  cllVctcd  by  a  spasmodic  shortening 


Fig.  200.    nichogamous   flower  of   Milchrlla   in    first   stage.     270.    The  same,  in  second   stage.     271. 
Dicliogamous  flower  of  Vernoriia  in  first  stage.    272.  Style  of  same  in  second  stage. 


of  the  stamens  ni)on  the  instant  of  contact  by  a  visiting  insect,  the 
pollen  being  by  the  same  process  at  once  discharged  iii)on  tiie  Ixidy  of  the 
latter.  After  the  removal  of  the  j)ollcn,  or  after  the  (k-ath  of  such 
grains  as  fail  to  be  removed,  the  style-l)ranches  .separate  (Fig.  '272)  in 
readiness  to  receive  the  pollen  brought  from  .some  other  flower.  This 
method,  or  some  modification  of  it.  is  very  common  among  the  Co7u- 
positae,  and  illu.strates  how  the  study  of  pollination  serves  to  explain 
many  modifications  of  flower-structure  otherwi.se  inex])lieable,  and  why 
the  possession  of  tlic  latter  is  reganh'd  by  the  biologist  as  indicating  a 
higher  stage  of  de\clo])ineiit. 

Dichogamy  is  very  conmion   among  perfect   aiieni()i)liil()us  flowers, 


96  POLLINATION  AND  FERTILIZATION 

where  self-pollination  would  otherwise  commonly  result,  and  it  may 
be  assumed  to  have  been  the  first  step  toward  the  uni-sexual  state,  so 
common  among  flowers  of  that  class.  Careful  notice  should  be  taken 
of  the  fact  that  in  dichogamy  the  retarded  state  observed  in  androecium 
or  gynaecium  is  but  temporary,  and  that  the  finally  develc^ed  form  is 
the  same,  whether  the  flower  be  proterandrous  or  proterogynous. 

Dimorphism. — A  far  more  profound  modification  is  that  in  which  there 
is  a  permanent  change  in  the  androecium  (Fig.  273)  of  one  flower  and 
a  similar  change  in  the  gynaecium  (Fig.  274)  of  another,  by  which  a 
similar  result  is  obtained  to  that  proceeding  from  dichogamy.  Such 
a  provision  constitutes  Dimorphism.  By  a  modification  of  it,  a  third 
form  of  flower,  intermediate  between  the  other  two,  is  produced,  con- 
stituting Trimorphism.  The  explanation  of  the  case  of  dimorphism 
here  exhibited  is  as  follows :   An  insect  visiting  flower  No.  1  and  thrusting 

his  proboscis  deeply  into  the  corolla- 
tube  in  search  of  nectar,  brings  his 
body  into  contact  with  the  stamens, 
and  pollen  is  deposited  upon  it.  The 
next  flower  visited  may  be  one  like 
2/^4^  No.  2,  having  a  long  style.  The  por- 
tion of  the  body  which  is  now  covered 
with  pollen  will  then  be  brought  into 

Fig.  273.  Long-styled  form  of  dimorphous  COUtact  with  the  StigUia,  UpOH  wllich 
aoy^er  of  Houstonia.    274.   The  same,  long-       ^j^^  jj^^^    j^    dcpOsitcd.      At    the   SamC 

staminate  form.  ^ 

time  a  different  part  of  the  body  is 
being  laden  with  pollen  from  the  short  stamens  of  flower  No.  2,  to  be 
deposited  upon  the  short  pistil  of  still  another  flower,  similar  to  No.  1. 
If  perchance  two  flowers  of  the  same  form  are  visited  in  succession,  the 
result  is  that  an  additional  deposit  of  pollen  is  secured,  or  at  most  a 
portion  of  the  pollen  already  being  carried  is  left  upon  the  stamens  of 
the  visited  flower. 

As  will  be  seen  by  a  consideration  of  typical  examples  of  each,  dimor- 
phism is  more  intimately  connected  with  the  transferring  of  the  pollen 
than  is  dichogamy,  though  the  latter  is  rarely  without  some  special 
provision  for  thus  supplementing  the  effect  which  it  produces  in 
excluding  the  pollen  from  the  stigma  of  its  own  flower. 

In  conclusion,  it  may  be  said  that  even  if,  by  some  failure  in  the 
provision  here  described,  the  flower  should  become  self-pollinated,  we 
have  excellent  reasons  for  believing  that  pollen  from  a  different  flower 
which  might  be  deposited  at  the  same  time  would  find  an  advantage 


CLEISTOGAMY  97 

accorded  to  it  by  whicli  it  would  he  enabled  to  first  reach  and  fertilize 
the  ovules. 

Coercion  of  Insect  by  Special  Forms. — The  assuming  of  a  form  con- 
venient for  the  visiting  insect,  to  which  reference  has  been  made,  is 
very  frequently  interfered  Math  for  the  purpose '  of  forcing  the  insect 
into  such  a  position  as  shall  favor  or  compel  the  removal  of  the  pollen, 
a  labor  which  is  by  no  means  agreeable  to  it  and  which  it  not  rarely 
seeks  to  avoid,  as  in  the  case  of  the  bee,  which  cuts  a  hole  at  the  base 
of  some  corollas,  through  which  its  food  may  be  extracted. 

No  better  illustration  of  such  coercion  of  the  insect  by  special  form 
could  be  selected  than  that  of  the  Asclepias  (Fig.  27G).  The  nectary  is 
at  a,  in  the  bottom  of  a  large  slipper-shaped  pouch.  Into  this  pouch 
the  insect  would  naturally  thrust  its  proboscis  in  the  direction  of  the 


276. 

Fig.  275.    Highly  magnified  papillose  stigmatic  surface.    276.    Vertical  section  of  flower  of  Asclepias: 
a,  nectary;   b,  blind  pouch;   c,  horn;   d,  pollinium;   e,  glutinous  corpuscle  of  same;  /,  stigma. 

point  b,  thus  avoiding  contact  with  the  pollen.  The  appendage  c, 
however,  cuts  off  this  line  of  approach,  sei)arating  the  blind  pocket  b 
from  the  nectary  a.  In  order  to  reach  the  latter,  the  insect  is  now 
forced  to  seek  an  entrance  at  the  ])oint  d,  his  head  being  thus  forced 
into  contact  with  the  pollen  at  e,  which  adheres  and  is  carried  away  to 
be  applied  to  the  stigma/  of  the  next  flower  visited. 

In  spite  of  the  possibility  of  thus  effecting  a  rough  classification  of 
some  of  the  methods  of  securing  cross-pollination,  it  is  yet  true  that  the 
great  majority  of  instances  are  not  subject  to  classification  and  must  be 
denominated  special,  or  else  that  they  combine  some  si)e(ial  arrange- 
ments with  such  general  methods  as  have  been  described. 

Cleistogamy. — Flowers  which  are  self-fertilized  before  exi)ansion  are 
Clei.stogamous.      Occasionally,    fertilization    takes    i)laee    without    the 
removal  of  the  pollen  from  the  anther. 
7 


98  POLLINATION  AND  FERTILIZATION 

Fixation  of  the  Pollen. — The  pollen  thus  transferred  to  the  stigma 
must  be  fixed  there  in  order  that  fertilization  may  follow  pollination. 
This  process  is  effected  by  contrivances  little  less  elaborate,  although 
more  minute,  than  those  which  have  been  described.  These  con- 
trivances relate  in  part  to  peculiarities  of  the  pollen.  As  regards  the 
stigma,  fixation  is  effected  most  generally  by  means  of  the  viscid 
secretion  to  which  reference  has  been  made,  the  stigma  being  essentially 
glandular  in  nature.  Appendages  in  the  form  of  hairs,  scales,  or 
papillae  (Fig.  275)  are  very  common.  In  some  cases  the  divisions  of 
the  stigma  are  sensitive  and  close  elastically  upon  the  pollen  as  soon 
as  it  is  deposited.  With  the  fixation  of  the  pollen  upon  the  stigma, 
pollination  is  completed  and  preparations  for  fertilization  begin. 

FERTILIZATION 

A  knowledge  of  fertilization  is  of  importance  to  the  pharmacognosist 
only  as  it  throws  light  upon  the  characters  of  the  fruit,  in  which  we 
include  the  seed  as  a  part.  Only  the  principal  facts  connected  with  the 
subject  will,  therefore,  be  here  considered. 

Internal  Structure  of  the  Ovule. — The  gross  appearance  and  parts  of 
the  ovule  have  already  been  described.  Its  internal  structure  is  illus- 
trated in  Fig.  277. 

The  immediate  function  of  the  flower  has  been  seen  to  be  the  pro- 
duction of  spores.  These  spores  are  to  act  as  reproductive  bodies,  which, 
like  seeds,  they  can  do  only  by  germinating  and  growing  in  a  suitable 
soil.    This  function  of  each  will  now  be  considered. 

We  have  seen  that  the  macrosporophyll  is  the  carpel,  its  macro- 
sporange  the  ovary.  The  macrospore  itself  is  the  large  centrally 
located  cell  of  the  nucellus,  which  is  to  develop  into  the  embryo-sac,  e. 
The  natural  soil  for  the  germination  of  this  spore  is  the  tissue  of  the 
nucellus  where  it  is  formed.  Its  germination  takes  place  immediately 
and  results  in  the  development  of  the  several  distinct  bodies  figured  in 
the  illustration.  Of  these  bodies,  the  oospore  or  vegetable  egg,  o,  is 
the  ultimate  female  reproductive  element. 

The  Gymnospermous  Ovule. — The  OA'ule  of  gymnosperms  agrees  in 
the  possession  of  an  embryo-sac,  with  several  bodies  corresponding  to 
the  oosphere  of  angiosperms,  but  with  the  other  corpuscles  not  clearly 
developed.  The  foramen  is  secretory,  so  as  to  be  adapted  to  acting 
upon  the  pollen-grain  which  it  receives,  as  does  the  stigma  in  angio- 
sperms. 


77//';   roLLKX-TUBE  99 

The  Female  Gametophyte.-  As  is  tlic  i)r<)(Iii(t  of  seod-germination, 
so  is  the  product  of  sixuv-uvnuiiiatioii  a  plant.  The  plant  which  results 
from  seed-germination,  and  wliicli  ])r()duces  spores,  has  been  called  a 
si)orophyte.  That  which  results  from  spore-germination,  and  the 
ultimate  function  of  which  is  the  production  of  seed;  is  called  a  gameto- 
])hyte.  Hence  the  mass  contained  within  the  embryo-sac  is  such  a 
l)lant.  the  female  gamctophyte.  It  will  rest  in  the  state  in  which  we 
now  find  it  until  its  oiisphere  is  acted  upon  by  the  male  element,  which 
wc  ha\e  yet  to  consider,  and  if  such  action  does  not  occur,  it  will  die 
and  (lisa])pear. 

Connection  between  Stigma  and  Ovule. — Between  the  ovule  thus 
prepared  and  the  stigma,  there  is  an  almost  continuous  connection 
through  conducting  tissue,  extending  through  the  body  of  the  stigma, 
style,  and  placenta.  The  extent  of  this  conducting  tissue,  like  that  of 
the  stigmatic  surface,  is  usually  greater  or  less  according  to  whether 
there  are  more  or  fewer  ovules  to  be  fertilized. 

We  have  seen  that  the  soil  u]K)n  which  the  microspore  is  intended  to 
germinate  is  the  stigma,  in  angiosperms,  and  the  foramen  of  the  ovule 
in  gymnosperms.  The  process  of  germination  is  dependent  upon  the 
following  structural  characters: 

Structure  of  the  Microspore.^ The  ])()llcn-grain  consists  of  a  highly 
hygroscopic  mass  of  tissue,  ])artly  vital  and  ])artly  nutritive,  the  latter 
of  variable  composition,  surrounded  !)>■  a  thin,  iion-])erforated,  highly 
elastic  membrane,  the  Intine,  and  this  in  turn  by  a  thicker,  non-elastic 
covering,  the  Extine,  or  "Exine,"  bearing  one  or  more  comi)lete  per- 
forations, very  thin  ])laces,  or  otherwise  modified  ])oints  u])on  its  surface. 
In  exce])tional  cases  there  is  instead  but  a  single  wall. 

Germination  of  the  Microspore. —  The  ])rocess  of  fertilization  is  illus- 
trated l)\-  Fig.  27s,  and  the  onhiiary  jjhciionicna  are  as  follows:  The 
l)ollen  grain  (a),  fixed  \i\un\  the  stigma  of  the  angiosjierm,  or  upon  the 
sununit  of  the  o\ule  of  the  gymnos])crni,  the  hygroscoi)ic  contents 
absorb  moisture  from  the  secreting  or  transuding  surface  with  which 
it  is  in  contact,  the  nuiss  increases  in  si/e  and  distends  the  intine  which 
surrounds  it.  Shortly  ccll-di\ision  of  its  contents  takes  place,  the  com- 
i)ined  changes  constituting  the  germination  of  the  micros]>ore. 

The  Pollen-tube.— Through  one  or  more  of  the  ])erforations  of  tlu> 
extine  already  existing,  or  forcii)ly  made  )>>  this  ])ro(ess,  ])rotrude 
prolongations  of  the  pollen  contents,  still  cnxcioped  in  a  |)rocess  of  the 
intine.    Such  a  i)roIongation  is  known  as  a  Pollen-tube  {h). 


100 


POLLINATION  AND  FERTILIZATION 


The  Male  Gametophyte. — A  body  of  this  kind,  proceeding  from  the 
germination  of  a  matured  spore,  is  properly  to  be  regarded,  Hke  its 
female  homologue,  as  a  plant  body.  It  is  to  be  noted,  in  passing,  that 
it  can  be  equally  well  produced  by  germination  upon  other  surfaces 
which  present  the  proper  conditions. 


Fig.  277.  Diagram  illustrating  structure  of  ovule:  s,  synergidae;  o,  o6sphere;  sek,  nucleus;  e, 
embryo-sac;  g,  antipodal  cells.  278.  Diagram  illustrating  fertilization:  a,  pollen-grains  on  stigma; 
h,  pollen-tubes  penetrating  stigma  and  style  and  entering  ovarian  cavity,  one  of  them  entering  the 
foramen  of  the  ovule  at  c. 


Following  the  same  course  of  reasoning  as  in  the  case  of  the  female 
gametophyte,  we  see  that  this  pollen-tube  is  the  male  gametophyte. 
Its  structure  is  not,  or  apparently  not,  even  so  highly  developed  as  in 
the  case  of  the  other. 

The  Male  Cell. — At  its  lower  end  are  one  or  more  little  bodies  which 
constitute  the  male  element  and  which  are  to  fertilize  the  oosphere 
which  we  have  already  observed  within  the  embryo-sac.  This  fertil- 
izing element  is  the  INIale  Cell,  or  Antherozoid. 

In  some  of  the  lowest  of  the  flowering  plants,  and  in  most  of  the 
Cryptogams,  this  male  cell  is  highly  organized,  with  a  specially  formed 
body,  is  capable  of  locomotion,  and  possesses  peculiar  powers  of 
nutrition.     It  is  comparable  with  the  spermatozoon  of  animals. 

The  Descent  of  the  Pollen-tube. — The  male  cell  or  antherozoid  is  quite 
as  incapable  of  reproducing  by  itself  as  is  the  oosphere,  and  its  sole 
function  is  to  act  upon  the  latter,  fecundating  it.    This  is  accomplished 


THE  DESCENT  OF   THE  POLLEN-TUBE  101 

by  the  penetration  of  the  loose  celkihir  tissue  oi  tlie  stigma,  then  of  tlie 
style,  by  the  pollen-tube.  Nourishment  for  its  growth  and  movement 
is  afforded  partly  by  the  contents  of  the  pollen-mass  and  partly  by 
absorption  from  the  tissues  of  the  stigma  and  style  with  which  it  is  in 
contact.  This  process  is  known  as  the  Descent  of  the  Pollen-tube,  and 
by  it  the  male  cell  or  antherozoid  is  brought  into  the  ovarian  cavity  and 
into  the  immediate  presence  of  the  ovule.  It  then  finds  the  foramen 
of  the  latter,  contact  and  fusion  of  the  male  cell  with  the  oosphere  is 
effected,  and  fertihzation  is  accomplished. 

Among  cryptogams,  there  are  no  such  speciallj'  adapted  sites  pro- 
vided upon  the  plant-body  of  the  parent  for  the  germination  of  spores, 
which  reproduce  upon  any  appropriate  soil.  They  may  be  of  two 
sexes,  the  macrosjiore  resulting  in  a  gametophyte  which  produces 
female  cells,  the  microspore  in  one  which  produces  antherozoids,  or  the 
one  gametophyte  may  produce  both  organs.  In  either  case,  the  anthero- 
zoids commonly  tray  el  to  reach  the  female  cell.  Fertilization  occurs 
very  much  as  in  phanerogarns,  but  no  seed  is  produced,  as  will  shortly 
be  explained,  the  embryo  proceeding  at  once  to  grow  and  reproduce  a 
sporophyte. 


CHAPTER    X 

CARPOLOGY:   FUNCTIONS  AND   STRUCTURE   OF   THE   FRUIT 
FRUCTIFICATION 

Fructification  and  its  Objects, — The  changes  effected  by  fertiHzation 
extend  to  all  parts  of  the  flower  and  even  to  other  parts  of  the  plant. 
A  consideration  of  the  objects  of  the  process  will  prepare  us  to  under- 
stand the  nature  of  the  changes.  The  objects  are  (1)  the  production 
and  maturing  of  one  or  more  seeds,  including  provisions  for  their  pro- 
tection and  nourishment  throughout  the  process,  together  with  the 
nourishment  of  the  parts  w^iich  thus  protect  them;  (2)  provisions  for 
their  transfer,  still  enclosed  in  their  container,  to  a  suitable  place 
for  germination  and  the  fixation  of  the  latter  there,  or  (3)  provisions  for 
their  exit  from  such  container  and  (4)  their  transfer  after  such  exit  to 
the  place  of  germination  and  their  fixation  there.  The  combined  pro- 
cesses connected  with  the  attainment  of  these  objects  is  Fructification, 
and  the  product  thereof  is  the  Fruit. 

Fructification  Results  in  the  Death  of  Some  Parts,  the  Stimulation  of 
Others. — It  is  clear  that  the  energies  of  the  plant  should  not  l)e  called 
for  in  the  further  development  or  preservation  of  any  parts  of  the  flower 
which  .are  not  serviceable  as  a  part  of  the  fruit  in  the  attainment  of 
the  above-named  objects,  unless  possibly  they  may  possess  some  other 
function  foreign  thereto,  as,  for  instance,  the  action  of  the  stamens  of  a 
flower  in  which  fructification  has  already  begun,  in  fertilizing  the  ovules 
of  some  other  flower.  We  should,  therefore,  look  (a)  for  the  disap- 
pearance or  death  of  all  floral  parts  not  thus  serviceable,  and  (6)  for 
the  stimulation  and  development  of  those  which  are.  That  the  first  of 
these  two  objects  is  an  immediate  result  of  fertilization  is  strikingly 
and  unhappily  illustrated  in  the  behavior  of  ornamental  flowers  in  which 
the  latter  process  is  allowed  to  take  place.  Those  who  produce  for 
the  market  the  handsome  and  expensive  flowers  of  orchids  are  obliged 
to  carefully  exclude  insects  from  their  greenhouses.  Valuable  flowers 
which,  without  fertilization,  would  last  for  several  weeks,  wither  and 
die  within  a  few  days,  or  even  hours,  after  such  process  has  occurred. 
That  the  accomi)lishment  of  the  second-named  object  is  no  less  imme- 
diate is  apparent  upon  considering  the  morphology  of  the  fruit. 


A^^IT"  PARTS  DEVELOPED  BY  FRUCTIFICATION  103 

Parts  Useless  in  Fructification. — The  only  i)()rti()n  of  the  flower  which 
is  certain  to  he  in  no  case  utihzed  in  fructification,  and,  therefore,  to 
disappear  after  fertiHzation,  is  the  actual  stigma,  and  the  stamens  when 
they  are  non-adlicrent.  The  stamens,  as  has  been  shown,  may  be  ser- 
viceable for  other  purposes,  so  that  their  death  depends  rather  upon 
the  performance  of  their  inchxichial  function  than  upon  fertihzation. 
In  proterogynons  flowers  this  function  is  actuall\-  stinnilate(l  by  the 
conii)k'tion  of  fertiH/ation  in  their  own  flower. 

Parts  Useful  in  Fructification. — Upon  the  other  hand,  we  are  not 
certain  of  a  requisition  in  every  case  for  the  preservation  and  develop- 
ment of  any  part  other  than  the  particular  ovules  which  l)ecome  fer- 
tilized, the  ovarian  walls  of  the  i)istil  or  pistils  containing  them  (and 
in  some  cases  only  a  part  of  these),  and  of  the  torus.  The  death  or 
decay,  therefore,  of  any  or  all  of  the  other  parts  will  be  determined  by 
the  indiA-idnal  or  class  habit  of  the  plant  concerned. 

Accrescent  Parts. — To  any  part  other  than  the  ovary,  which  thus 
develops  and  enlarges  as  a  part  of  the  fruit,  the  term  Accrescent  is 
ai)plie<l. 

Accessory  Fruits. — Fruits  of  which  such  accrescent  i)arts  form  the 
conspicuous  ])ortion  are  called  Accessory  fruits. 

New  Parts  Developed  by  Fructification. — Finally,  we  must  note  that 
new  ])arts,  of  service  in  the  fruit,  frequently  develop  in  the  course  of 
fructiflcation,  u])on  either  pericarj)  or  seeds,  just  as  special  a])])endages 
develop  u))on  the  floral  organs  for  performing  special  function  in  con- 
nection with  pollination.  That  such  additional  parts  exhibit  little,  if 
any,  (le\-eloi)nient  (Jui'ing  the  floral  stage,  is  due  to  the  fact  that  an 
enormous  waste  of  energy  on  the  i)art  of  the  plant  would  thus  be 
involved.  Of  all  the  flowers  j)roduce(l  by  a  plant,  only  a  niiiioi-  ])ortion 
usually  accom])lish  fructiflcation,  and  of  all  the  ovules  produced  by  any 
gynaecium  only  a  minor  j)ortion  usually  produce  seeds.  The  develop- 
ment of  these  su])erfluous  flowers  and  o\ules  constitutes  in  itself  a 
serious  waste,  l)ut  it  is  a  necessary  or,  upon  the  whole,  an  economical 
one,  as  it  tends  in  the  end  to  secure  the  full  degree  of  fructification  by 
tiie  plant.  The  develojiment,  however,  upon  such  superfluous  flowers 
or  ovules,  of  parts  which  will  be  of  value  only  in  case  fructiflcation  is 
effected,  would  be  anything  l)ut  (>cononiieal.  Hence  the  general 
rule  that  ])arts  of  the  fruit  which  are  of  no  use  in  elfiM-ting  ])ollination 
and  fertilization  are  not  (le\-elope(l  until  after  these  functions  are 
performed. 


104     CARPOLOGY:  FUNCTIONS  AND  STRUCTURE  OF  THE  FRUIT 

FRUIT 

Structural  and  Physiological  Senses  of  the  Term, — There  are  two  dis- 
tinct senses  in  which  the  term  "fruit"  may  be  employed.  In  the  first 
instance,  we  may  regard  it  as  the  structural  product  of  the  develop- 
ment in  fructification  of  a  pistil,  or  in  the  second  as  an  organ  performing 
a  certain  reproductive  function  or  functions.  The  limitations  of  our 
definition  of  the  term  will  vary  accordingly. 

Entire  Gynaecium  as  the  Fruit. — In  many  cases  the  ripened  gynaecium 
performs  or  may  perform  the  fruit-function  entire,  as  in  the  cherry, 
the  strawberry,  the  blueberry,  the  so-called  "seed"  of  the  sunflower,  or 
the  pod  of  the  bean  or  digitalis.  In  such  cases  the  solitary  ripened 
carpel  (cherry  and  bean)  or  the  aggregation  of  ripened  carpels  (as  in  the 
other  illustrations),  of  a  gynaecium,  constitutes  the  fruit,  from  either 
point  of  view. 

Either  the  Whole  or  Part  of  a  Gynaecium  as  a  Fruit. — In  other  cases  the 
several  carpels  of  a  gynaecium  are  separate  from  first  to  last  as  pistils, 
as  in  the  case  of  the  buttercup.  The  entire  collection  then  constitutes 
a  fruit,  being  the  product  of  a  flower,  but  each  of  the  individual  pistils 
must  also,  from  a  physiological  standpoint,  be  regarded  as  a  fruit,  inas- 
much as  it  performs  the  fruit  function  independently. 

Part  of  a  Pistil  as  a  Fruit. — Again  we  find,  as  in  the  case  of  the  borage, 
that  carpels  originally  coherent,  separate  before  performing  their 
function,  so  that  we  must  regard  each  of  the  separated  carpels,  as  well 
as  the  entire  gynaecium,  as  in  the  nature  of  a  fruit. 

Part  of  a  Carpel  as  a  Fruit. — Occasionally  even  a  carpel  will  itself 
divide  into  separate  parts,  each  of  which  is  equally  entitled  to  be 
designated  as  a  fruit,  as  in  the  case  of  the  2  carpels  of  the  lavender, 
which  separate  into  4  nutlets. 

Gynaecia  of  a  Number  of  Flowers  Forming  a  Fruit. — In  still  other  cases 
the  ripened  gynaecia  of  more  than  one  flower  cohere  and  perform  the 
fruit  function  as  one  body,  as  in  the  case  of  the  partridge-berry,  the 
fig,  and  the  mulberry. 

Finally,  we  note  that  many  fruits  can  perform  their  function  in  either 
way — namely,  by  means  of  their  carpels,  or  parts  thereof  individually, 
or  as  aggregations  proceeding  from  a  single  flower  (blackberry),  or 
from  many  flowers  (fig,  hop,  etc.).  It  is,  therefore,  to  be  noted  that 
that  which  is  at  one  time  to  be  regarded  as  a  fruit  is  at  another  time 
only  a  part  of  one,  according  to  the  manner  in  which  it  performs  its 
function. 


THE  PERICARP  105 

Kinds  of  Fruits. — From  the  foregoing  considerations,  we  may  deduce 
the  following  definitions  of  fruits: 

A  Fruit  is  a  separate  ripened  carpel,  or  a  separate  part  thereof,  or  an 
aggre,c;ation  of  ripened  carpels,  together  with  any  adherent  j)arts. 

Multiple  or  Collective  Fruits  are  those  proceeding  from  the  gynaecia 
of  more  than  one  flower. 

Aggregate  Fruits  are  those  which  proceed  from  a  number  of  pistils 
of  one  flower. 

Simple  Fruits  are  those  proceeding  from  a  single  pistil. 

Apocarpous  Fruits  are  those  consisting  of  one  carpel  or  of  two  or 
more  non-coherent  carpels. 

Syncarpous  Fruits  are  those  consisting  of  coherent  carpels. 

Accessory  Fruits  are  those  in  which  some  part  other  than  the  ripened 
ovary  constitutes  a  conspicuous  portion. 

Structural  Composition  of  the  Typical  Fruit. — The  student  cannot  have 
failed  to  note  in  reading  the  above  statements  that  the  composition  of 
the  fruit  is  extremely  variable  and  in  some  cases  complicated.  In 
accordance  with  this  fact,  the  classification  of  the  parts  of  fruits  is 
o])en  to  great  differences,  according  to  the  principles  upon  which  the 
observer  bases  his  classification.  The  typical  fruit  may  be  considered 
as  that  which  consists  only  of  the  ripened  pistil  with  the  contained  seed 
or  seeds. 

The  Pericarp. — As  a  fruit  is  regarded  as  possessing  but  two  portions, 
namely,  the  seeds  and  the  Pericarp,  the  pericarp  of  such  a  tyi)ical  fruit 
would  consist  of  a  ripened  })istil  exclusive  of  its  seeds,  but  since,  in  many 
cases,  the  calyx,  disk,  or  other  part  is  closely  adnate  to  the  wall  of  the 
ovary  and  more  or  less  indistinguishable  from  it,  it  becomes  imprac- 
ticable to  restrict  the  term  pericarp  to  a  part  consisting  only  of  the 
pistil.  Again  we  find  that  there  are  all  intermediate  forms  and  degrees 
of  adnation  and  sei)aration  between  the  ovary  and  the  accrescent  ])arts 
of  accessory  fruits.  It,  therefore,  appears  most  convenient  to  define 
the  pericarp  in  a  broad  sense  as  the  fruit  with  the  exception  of  the 
seeds. 

The  Pseudocarp  or  Anthocarp. — AVhen  the  pericarj)  consists  chiefly 
of  other  elements  than  the  ovarian  wall  it  is  called  a  Pseudocarp  or 
Anthocarp. 

Layers  of  the  Pericarp. — When  the  pericarp  is  seen  to  consist  of  three 
demonstrable  layers,  these  are  called  respectively  Fxocarp,  the  outer; 
Endocarp,  the  inner;  and  Mesocarp,  the  middle.  When  the  exocarp 
is  thin  and  membranous,  like  the  skin  of  a  plum,  apple,  or  tomato, 


106     CARPOLOGY:  FUNCTIONS  AND  STRUCTURE  OF  THE  FRUIT 

it  is  called  an  Epicarp,  and  when  an  endocarp  is  hard  and  strong  inside 
of  a  fleshy  layer,  like  the  stone  of  a  peach  or  the  "core"  of  an  apple,  it 
is  called  a  Putamen. 

Modes  of  Performance  of  the  Fruit  Functions. — We  shall  now  consider 
the  maimer  in  which  tlie  fonr  objects  of  fructification  are  accomplished 
through  the  modifications  effected  in  each  of  the  floral  parts  and  in 
the  parts  adjacent,  by  fertilization,  including  such  new  appendages 
as  are  thus  caused  to  develop. 

Growth  and  Maturity. — The  development  and  maturity  of  the  fruit 
are  eft'ected  by  the  stimulation,  through  fertilization,  of  the  nutritive 
functions  of  the  pistil,  the  torus,  adjacent  portions  of  the  plant,  and 
through  the  combined  influence  of  all  the  flowers,  a  similar  stimulation 
of  all  portions  of  the  plant. 

Protection. — So  far  as  the  development  of  a  protecting  container  for 
the  maturing  seed  is  concerned,  the  object  in  general  demands  the 
development  of  nothing  more  than  the  ovarian  wall;  but  the  effects  of 
adnation  and  the  requirements  of  the  other  objects  result  in  the  exten- 
sion of  this  process  to  various  other  parts  of  the  flower  or  even  of  its 
supporting  parts.  The  development  of  such  parts  in  connection  with 
the  ovarian  walls  will  therefore  receive  attention  in  considering  the 
methods  by  which  such  other  objects  are  accomplished. 

The  Abortion  of  Septa  and  Cells. — It  has  been  stated  that  not  always 
are  all  of  the  ovarian  walls  involved  in  fruit  development.  A  gynae- 
cium  possessing  several  pistils  may  fail  to  develop  one  or  more  of  them 
in  fruit,  and  when  these  are  adnate  into  a  compound  o^'ary,  as  in  Val- 
lesia,  one  or  more  of  them  may  likewise  fail  to  develop.  A  several- 
celled  ovary,  as  in  Calesium  (Fig.  279),  may,  after  the  fertilization  of 
one  or  more  ovules  in  one  or  more  cells,  permit  the  abortion  of  those  in 
the  other  cells,  the  septa  of  the  latter  being  then  crowded  against  the 
outer  wall  by  the  growing  seeds,  or  even  disappearing,  so  that  the  fruit 
will  contain  a  smaller  number  of  cells  than  the  ovary  which  produced  it. 
The  partial  obliteration  of  cells  in  a  similar  manner  is  well  shown  in  the 
fruit  of  Diospyros  {Fig.  280). 

Mr.  J.  H.  Hart  has  contributed  three  fruits  taken  from  one  crop  of 
a  single  plant  (Fig.  285,  a,  b,  and  c),  the  first  showing  the  development 
of  all  three  of  the  ovarian  cells,  the  others  having  respectively  one  and 
two  of  these  aborted. 

The  Development  of  New  Septa  and  Cells. — x4dditional  walls,  upon  the 
other  hand,  may  develop  during  fructification.  Datura  has  a  2-celled 
ovary  (Fig.  221),  but  a  4-celled  fruit  (Fig.  223),  and  this  occurs  regularly 


TRAASl'ORTATIOX  OF   THE  FRUIT 


107 


in  the  Labidfar.  Tlie  newly  formed  walls  are  not  always  vertical.  The 
fruit  of  Arsrlii/noiiwne  (Fig.  351)  and  that  of  Sophora  (Fig.  352)  divide 
trans\(M-seiy  into  one-seeded  joints. 

Special  Defensive  Provisions,  ("oneerning  the  protection  of  tlii'  fruit 
and  seeds,  we  note  that  its  full  accomplishment  often  calls  for  other 
defensive  i)rovisions  than  those  against  merely  mechanical  forces,  in 
the  form  of  appendages  constituting  an  armor.  These  are  sometimes 
an  outgrowth  from  the  ovary  itself,  as  in  Sfnuiioniinn  (Fig.  282),  some- 
times u])on  an  enclosing  calyx  (Fig.  283),  an  enclosing  wall  consisting 
of  a  hollowed  branch, ;is  ni  tlu>  i)rickly  pear  (Fig.  281 ),  or  soinetiines  upon 


Fig.  279.  Cro-ss-sfction  of  yoiiiiK  fruit  of  Calcsium,  the  cells  tlisappuiiriiis;  uxicpt  that  in  wliich  an 
ovule  has  been  fertilized.  2S0.  Diospyros,  the  same.  2S1.  Fruit  of  Opuntia,  immersed  in  prickly  end 
of  branch.  282.  F'ruit  of  Datura,  with  prickly  ovary.  283.  Of  Riancjc, with  prickly  calyx.  284.  Of 
Castena,  with  prickly  involucre.  285.  Three  palm-fruit.s  from  the  same  tree,  with  one  or  two,  a,  with 
none,  of  the  cells  aborted. 

an  enclosing  involucre,  as  in  the  chestinit  burr  (Fig.  284).  At  other 
times  the  protection  is  secured  by  develoi)ing  acrid  or  otherwise  dis- 
agreeable pericarps,  as  the  husk  of  the  walnut  or  the  pulp  of  the  colo- 
cynth.  These  defences  may  be  ett'ective  only  during  the  maturing  stage, 
as  already  pointed  out,  or  their  deterrent  action  may  be  permanent. 
In  tlie  same  direction  are  to  be  considered  the  effects  of  ])oi.sonous 
principles  proper  and  the  inedible  nature  of  a  pericarp  pending  the 
maturing  of  the  seed,  })ut  which  afterward  becomes  edible. 

Transportation  of  the  Fruit.-  The  transfer  of  the  fruit  to  the  jjlace  of 
germination  is  securetl  by  inctliods  which  for  the  ni(»t  part  admit  of 


108     CARPOLOGY:  FUNCTIONS  AND  STRUCTURE  OF  THE  FRUIT 

classification.  We  shall  first  consider  those  provisions  which  utilize 
the  agency  of  the  wind  for  this  purpose. 

Transportation  by  the  Wind. — We  note,  first,  that  the  weight  of  fruits 
to  be  thus  transported  is  reduced  to  a  minimum.  They  are  in  almost 
all  cases  one-seeded  (Monospermous),  the  loss  due  to  this  character 
being  made  good  by  the  fructification  of  a  large  number  of  flowers. 
The  one-seeded  condition  of  such  fruits  is  not  restricted  to  families 
which  are  characterized  by  it.  Many  fruits  of  the  Leguminosae,  which 
are  commonly  several-  or  many-seeded,  as  the  pea  and  bean,  become 
one-seeded  when  adapted  to  wind-transportation  (Figs.  296  and  299). 
Fruits  which  are  not  one-seeded  may  divide  into  one-seeded  parts, 
easily  separable,  to  facilitate  transportation  by  wind  or  other  agencies, 
as  has  already  been  shown. 

Morphology  of  Fruit-wings.— Such  a  state  having  been  attained,  the 
action  of  the  wind  upon  them  is  next  secured  through  the  development 
of  an  expanded  surface  of  some  kind,  commonly  a  wing  or  plume. 
In  the  Platypodium  (Fig.  296)  it  is  the  entire  wall  of  the  ovary,  in  its 
original  nature  a  pod,  like  that  of  the  bean,  which  becomes  developed 
into  a  wing.  In  the  elm  (Fig.  287)  it  is  likewise  the  ovarian  wall.  In 
the  carrot  (Fig.  288)  and  the  Rumex  (Fig.  289)  it  is  an  enclosing  accres- 
cent calyx.  In  the  Piptoptera  (Fig.  290)  it  is  two  accrescent  lobes  of 
such  a  calyx.  In  the  Zinnia  (Fig.  291)  a  persistent  corolla  performs 
the  same  office.  In  the  hop  (Fig.  292)  an  accrescent  bract  is  made  to 
serve  the  office  of  a  sail.  The  fruit  of  the  Cardiospermum  (Fig.  294) 
represents  a  class  in  which  the  thin  pericarp,  instead  of  being  expanded 
into  a  wing,  is  inflated  into  a  balloon-shaped  receptacle,  subserving  a 
similar  purpose.  Plumes,  consisting  of  the  modified  persistent  calyx, 
are  seen  in  the  Valerian  (Fig.  293)  where  it  is  present,  though  concealed 
by  a  circinate  praefloration,  from  the  flowering  stage,  while  in  the 
Phyllactis  it  is  not  developed  until  after  fructification  begins.  A 
plumose  style  is  seen  in  Pulsatilla  (Fig.  286). 

Transportation  by  Attachments. — We  shall  next  note  the  cases,  per- 
haps even  more  numerous,  wherein  use  is  made  of  passing  bodies  by 
providing  such  appendages  as  shall  serve  to  attach  the  fruit  to  them. 
Fig.  298  represents  the  fruit  of  a  Rumex,  in  which  the  calyx  is  divided 
into  hooks  for  this  purpose.  Fig.  297  shows  another  species,  in  which 
this  method  is  combined  with  wind  transportation,  a  combination  which 
is  very  common  among  the  Umbelliferae.  The  accrescent  calyx  teeth 
(awns)  of  Verbesina  (Fig.  295)  are  adapted  to  piercing  passing  bodies, 
while  at  the  same  time  the  adnate  tube  is  winged.    In  Bidens  (Fig.  300) 


TRANSPORTATION  OF  THE  FRUIT 


109 


similar  awns  arc  ])ar}H'(l  and  adhere  very  tightly  to  anything  which 
they  may  pierce.  In  the  case  of  the  burdock  (Fig.  301)  it  is  an  involucre 
which  bears  such  hooks.  Similar  hooks  are  found  upon  the  outer 
wall  of  the  ovary  itself  in  many  cases.  Sometimes  the  style  is  recurved 
at  the  apex,  thus  forming  a  terminal  hook,  while  at  others  (Fig.  302) 
the  apex,  after  performing  the  stigmatic  function,  falls  away,  but  leaves 
a  hooked  lower  joint  to  become  efl'ective  in  the  fruit.  The  attachment 
is  not  alw^ays  thus  secured  by  means  of  distinctively  piercing  appendages. 
The  surface  may  be  rendered  adhesive  in  other  ways,  as  seen  in  the 
minute  structures  covering  the  fruit  of  Desmodium. 


Fig.  286.  Fruit  of  Pulsatilla,  with  plumose  style.  287.  Winged  epicarp  of  Ulmus.  288.  Of  carrot. 
289.  Winged  calyx  of  Rumex.  290.  Of  Piptoplera.  291.  Winged  petal  of  Zinnia.  292.  Winged 
bract  of  hop.  293.  Plumose  calyx  limb  of  Vahriaita.  294.  Inflated  pod  of  Cardiospcrmum.  295. 
Winged  akene  of  Virhesina.  290.  Winged  legume  of  Plalypodium.  297.  Winged  and  hooked  calyx 
of  Rumex.  298.  The  same,  hooked  only.  299.  Winged  legume  of  Plerocarpus.  300.  Hooked  calyx 
of  Bidens. 


Trans porf (if ton  through  Edible  Pericarps. — We  shall  next  consider 
another  large  class  of  fruits,  which  dci)end  for  their  trans])()rtation  upon 
the  possession  of  cdil)le  pericarps  or  edible  portions  of  them.  Such 
fruits  may  be  eaten  with  the  contained  seed,  as  in  the  case  of  the  straw- 
berry or  small  cherries,  in  which  case  transportation  is  effected  during 
the  process  of  digestion  of  the  pericarj);  or,  as  in  the  case  of  the  peach 
and  ])lum,  the  fruit  may  be  too  large  for  such  process,  depending  for 
trans])ortation  upon  carriage  by  a  ])arent  to  its  young.  In  still  other 
cases  they  are  of  such  a  nature  that  they  can  be  carric<l  and  stored  for 


110     CARPOLOGY:  FUNCTIONS  AND  STRUCTURE  OF   THE  FRUIT 

winter  use.  The  edible  portion  is  in  some  cases,  as  in  that  of  the  banana, 
highly  nutritious,  while  in  others  it  is  apparently  eaten  merely  for  its 
palatability  or  for  its  thirst-quenching  properties. 

Special  Protection  to  Seeds  of  Edible  Fruits. — Some  special  form  of 
protection  is  commonly  required  for  the  seeds  of  edible  fruits.  That 
of  the  peach  is  enclosed  in  a  hard  stone,  so  that  it  shall  not  be  a})raded 
as  the  pulp  is  pecked  or  bitten  away.  Those  of  the  cherry  and  straw- 
berry are  enclosed  in  similar  hard  coats,  which  resist  the  digestive  process 
as  well.  The  more  or  less  laxative  or  purgative  properties  of  many 
fruits  doubtless  contribute  to  such  protection  by  the  more  prompt 
dejection  of  the  seeds  which  is  brought  about  by  their  action. 


J(?P. 


Fig.  301.  Lappa  fruit  with  prickly  involucre.  302.  Fruit  of  Gt-um  with  jointed  .style.  303.  Fruit 
of  Gaulthcria,  with  fleshy  calyx.  304.  Of  strawberry,  with  fleshy  torus.  305.  Of  blackberry,  with 
fleshy  torus  and  ovaries.  306.  Of  cashew,  with  fleshy  pedicel.  307.  Of  tamarind,  with  fleshy  middle 
layer  of  pod.  308.  Of  apple,  with  fleshy  calyx  and  disk.  309.  Of  papaw,  with  fleshy  inner  layer  of 
ovary.  310.  Of  belladonna,  with  fleshy  ovary.  311.  Of  fig,  with  fleshy  hollowed  end  of  branch. 
312.  Of  watermelon,  with  fleshy  placentae. 


Origin  of  Edible  Portion. — The  origin  of  the  edible  portion  is  various. 
In  the  strawberry  (Fig.  304)  it  is  the  complete  torus,  and  this  only.  In 
the  blackberry  (Fig.  305)  such  a  torus  is  combined  with  a  partially 
fleshy  ovarian  wall  upon  each  of  the  ripened  pistils.  In  the  rose  (Fig. 
59)  it  is  a  similar  torus,  but  hollowed,  probably  with  other  elements 
combined.  In  the  apple  (Fig.  308)  it  is  a  fleshy-thickened  disk,  together 
with  the  adnate  calyx  lined  by  it.  In  the  checkerberry  (Fig.  303)  it  is 
the  calyx  only  which  becomes  fleshy.  In  the  gooseberry  it  is  the  calyx 
and  the  entire  ovary,  but  without  any  disk,  while  in  many  other  berry- 
like fruits  it  is  the  ovary  alone.    In  the  plum  and  cherry  not  all  of  the 


SPECIAL  !>h'<)\/SI(>XS  FOR  I'RFA'KNTI  N(i  TUAXSl'OUTA  TION      1 1 1 

ovarian  wall  is  edible,  its  endoearp  heeomiiifjj  a  putaiiieii.  In  the  lemon 
(Fig.  329),  the  papaw  (Fig.  309),  and  the  pnnipkin  it  is  the  inner  i)ortion 
which  is  edible,  while  the  outer  is  not.  In  the  waterniclon  the  ])lacentae 
comprise  almost  the  whole  of  the  e(lil)le  ])ortion  (Fig.  '.\V1),  while  in  the 
tamarind  it  is  the  middle  layer  of  the  ovary  (Fig.  '.\()1). 

Edible  Portions  Not  Pertaining  to  the  Flower. — In  all  of  the  above- 
mentioned  cases  it  is  some  one  or  more  of  the  parts  of  the  flower  which 
eventually  forms  the  edible  i)eriear]),  but  there  are  numerous  cases  in 
which  other  parts  of  the  plant  contribute  to  or  form  the  whole  of  such 
l)()rti()n.  In  the  Cashew  (Fig.  ;>()())  the  ovary  (a)  enlarges  but  little, 
while  the  j)edicel  {b)  undergoes  a  great  enlargement  and  becomes 
edible.  In  the  cactus  (Fig.  281)  the  end  of  the  branch  is  hollowed  out 
and  the  wall  so  formed  l^ecomes  the  edible  pericarp  of  a  single  flower. 
In  the  fig  (Fig.  311)  we  have  a  similar  hollowed  branch,  but  instead  of 
being  occui)ied  by  a  single  flower,  the  wall  is  lined  by  a  great  number  of 
them. 

Miscellaneous  Methods  of  Transportaiion. — Besides  the  more  common 
methods  of  seed  distribution  referable  to  the  pericarp,  which  are  thus 
subject  to  classification,  we  find  numerous  special  devices  which  cannot 
here  be  enumerated  in  detail.  Fruits  which  grow  beside  or  in  the 
vicinity  of  streams  or  other  bodies  of  water  are  commonly  adapted  in 
some  way  for  using  the  latter  as  a  vehicle  for  transportation.  They  are 
freqnently  of  a  rounded  form  and  of  considerable  weight,  so  that  njion 
falling  they  will  roll  into  the  water,  where  they  are  then  enal)le(l  to 
float  i)y  virtue  of  low  specific  gravity,  due  often  to  the  presence  in  them 
of  large  cavities,  as  in  the  case  of  the  cocoanut.  The  pericarp  is  in  such 
cases  usually  furnished  with  some  means  of  protection  against  the  action 
of  the  water.  The  fruit  of  a  s])ecies  of  Arena  is  so  constructed  that  by 
the  change  of  form  and  position  of  its  long  awns  in  dry  and  wet  weather, 
respectively,  it  is  enabled  to  tra\"el. 

Special  Provisions  for  Preventing  Transportation.—  Finally,  we  must 
note  that  some  fruits  are  ])rotected  by  special  devices  against  trans- 
portation. Thus,  the  mangrove  possesses  a  seed  which  germinates  while 
still  attached  to  its  parent  and  which  does  not  sever  its  connections 
therewith  until  the  young  ])laiit  has  descended  many  feet  and  fixed 
itself  into  the  nuid  below.  The  jx'annt,  after  antlu'sis,  drixcs  its  o\ary 
beneath  the  surface  of  the  soil,  where  its  fruit  is  dexcloped  (  h'ig.  .■!]:!). 
Plants  ])()ssessing  such  habits  are  ahva\s  highly  gregai'ions,  ()ccu])yiiig 
the  ground  to  the  exclusion  of  all  other  species,  thus  .securing  their 
perpetuation  even  wliile  their  di.ssemination  is  prevented.     The  high 


112     CARPOLOGY:  FUNCTIONS  AND  STRUCTURE  OF  THE  FRUIT 

degree  of  adaptation  secured  by  the  peanut  is  still  further  illustrated 
by  its  apparent  power  to  support  itself  by  means  of  these  buried 
branches,  should  the  parent  stem  in  any  way  become  severed;  a  very 
important  protection,  in  view  of  the  highly  nutritious  character  of  the 
herbage,  which  renders  it  liable  to  partial  destruction  by  grazing 
animals. 


<3/J. 

Fig.  313.  Peanut  plant,  with  buried  fruits. 

The  Fixation  of  Fruits  after  Distribution. — The  fixation  of  many  fruits 
with  their  contained  seeds  is  secured  by  a  series  of  devices  no  less 
interesting  than  those  which  effect  their  distribution.  Fruits  like  those 
represented  in  Figs.  75,  76,  etc.,  are  commonly  more  or  less  sharpened 
or  narrowed  at  the  lower  end,  which  is  much  the  heavier,  so  that  they 
shall  the  more  readily  penetrate  a  favorable  surface.  Their  bodies, 
moreover,  are  commonly  toothed  or  hispid  upward,  so  that  the  tendency 
is  for  them  to  sink  more  and  more  deeply  until  properly  interred.  The 
fruit  of  Viscum,  whose  seed  can  develop  only  upon  the  bark  of  trees, 


DEHISCENCE  113 

is  intensely  adhesive,  so  that  in  i'alHng  it  does  not  readily  })ound  away, 
bnt  l)eoomes  adherent  to  the  first  sohd  l)ody  wliich  it  eneonnters. 

Provisions  for  Scattering  Seeds. — As  a  rule,  fruits  whieh  are  provided 
with  special  dexiees  for  their  transportation  are  not  designed  for  the 
discharge  of  the  contained  seed,  which  escapes  accidentally  or  germin- 
ates while  still  enclosed.  Provisions  for  the  discharge  of  seeds,  therefore, 
ordinarily  apply  only  to  such  fruits  as  complete  their  function  at  the 
place  of  origin.  For  provisions  for  the  distribution  of  such  plants,  we 
should  naturally  look  to  the  seeds  themselves;  yet  to  this  rule  there  are 
mnnerous  exceptions,  for  many  fruits  which  never  leave  the  place  of 
growth  yet  possess  various  devices  for  distributing  their  seeds  over  a 
greater  or  less  area  by  \irtue  of  forces  inherent  in  their  pericarps.  The 
common  name  of  the  Impatiens,  "touch-me-not,"  is  derived  from  the 
habit  of  its  fruit  of  exploding  with  much  force,  discharging  its  seeds 
meantime  to  a  considerable  distance.  The  fruit  of  Iliira  similarly 
explodes,  and  with  such  violence  as  to  cause  a  report  like  the  discharge 
of  a  firearm.  Elaterium  (Fig.  314),  during  the  ripening  process,  collects 
by  osmosis  within  its  cavity  an  amount  of  liquid  which  exerts  a  powerful 
outward  pressure  upon  the  pericarp.  When  fully  rijjc,  the  slightest 
contact  with  another  body  causes  the  pericarp  to  leap  away  from  its 
attachment,  with  the  production  of  a  hole  at  its  base  through  which 
the  seeds  are  expelled  with  much  force. 

Dehiscence. — The  ordinary  method  of  providing  for  seed  discharge  is 
by  means  of  a  splitting  of  the  pericarp  known  as  Dehiscence. 

Dehiscent  and  Indchiscent  Fruits. — A  fruit  so  splitting  is  said  to 
Dehisce,  and  is  known  as  a  Dehiscent  or  Dehiscing  fruit.  Other  fruits 
are  called  Indehiscent.  True  dehiscence  is  longitudinal,  although  the 
term  is  not  altogether  denied  to  other  forms,  provided  the  line  of 
separation  is  regular  and  constant  (Figs.  325-327). 

The  Valves. — The  parts  into  which  pericarps  dehisce  arc  called 
Valves.  The  valves  may  separate  entirely  or  remain  attached  in 
various  ways. 

Forms  of  Dehiscence. — Dehiscence  may  occur  at  the  ventral  or  at  the 
dorsal  suture  or  at  both.  If  at  the  ventral,  then  the  carpel  (Fig.  349), 
or  each  carpel  if  it  be  i)art  of  a  ])olycarpellary  ])istil  (Fig.  310),  will  be 
left  entire.  If  the  polycar])ellary  ])istil  have  se\eral  cells,  xcntinl 
dehiscence  must  involve  the  separation  of  the  carjjcls  by  the  si)litting  of 
their  walls  or  septa,  whereas  in  the  one-celled  form  se])ta  do  not  exist 
or  are  incomplete.  Nevertheless,  the  principle  is  identical  in  the  two 
cases,  and  the  former  mode  is  called  Septicidal  dehiscence  (Fig.  316). 
8 


114      CARPOLOGY:   FUNCTIONS  AND  STRUCTURE  OF   THE  FRUIT 

In  such  case  the  carpels,  after  separating  through  their  septa,  are  not 
necessarily  open,  and  unless  the  dehiscence  shall  follow  the  wall  into  and 


my 

^  ti'f 


J/4 


SIS. 


3/6. 


3/7 


Fig.  314.  Fruit  of  Elateriuvi  discharging  its  seeds  and  watery  contents.  315.  Loculicidally  dehiscent 
pod  of  7ns.  316.  Septicidally  dehiscent  pod  of  Hypericum.  317.  Transverse  diagram  of  a  margini- 
cidally  dehiscent  pod. 


Fig.  318.  Apical  dehiscence  of  Cerastium.  319.  The  same,  Eucalyptus.  320.  Circumscissile  dehis- 
cence of  Mitracarpus.  321.  Basal  dehiscence  of  Jussiaea.  322.  The  same  in  Cinchona.  323.  Apical 
dehiscence  of  Ladenhcrgia.  324.  Dehiscence  by  apical  plug  (6)  in  Berlholetia.  325.  Apical  dehiscence 
of  Psyllocarpus.  32C.  Oblique  dehiscence  of  Slaelia.  327.  Partial  dehiscence  of  Jeffersonia.  328. 
Dehiscence  by  apical  pore  in  Siphocampylos, 


through  the  ventral  suture,  which  it  more  frequently  does  not,  the 
dehiscence  will  be  Incomplete  and  the  carpels  may  even  act  as  separate 
indehiscent  fruits.    If  dehiscence  occur  at  the  dorsal  suture  (Fig.  315) 


DEHISCENCE  115 

it  must  separate  the  wall  of  the  cell  into  two  parts,  and  this  form  is 
called  Lociilicidal  dehiscence.  By  an  intermediate  form,  the  dehiscence 
takes  place  at  the  point  where  the  septum  joins  the  outer  wall  (Fig.  317), 
the  IMarginicidal  form.  Various  other  modifications  and  combinations 
of  the  two  forms  may  be  discovered,  but  do  not  call  for  a  notice  in  this 
work. 

Mechanism  of  Dehiscence.— Dehiscence  is  secured  by  a  peculiar  adap- 
tation of  the  fil)ers  to  the  other  tissues  and  to  the  form  of  the  fruit. 

Incomplete  Dehiscence. — \^arious  forms  of  imi)erfect  or  incomplete 
dehiscence  are  those  in  which  it  commences  at  the  apex  and  fails  to 
extend  itself  to  the  base,  as  in  Cerastium  (Fig.  318)  and  EvcalyjJtus 
(Fig.  319),  or  in  which  it  commences  at  the  base  and  extends  only 
partially  toward  the  apex,  as  in  Jnssiaea  (Fig.  321)  and  in  Cinchona 
(322).  Important  pharmaceutical  decisions  have  rested  upon  the 
question  of  basal  or  apical  dehiscence.  The  true  Cinchona  barks  have 
all  proceeded  from  species  whose  fruits  dehisce  as  represented  in  Fig. 
322,  while  those  of  the  trees  yielding  the  false  barks  dehisce  as  repre- 
sented in  Fig.  323. 

Syecial  Terms  for  Dehiscence. — The  manner  in  which  true  dehiscence 
passes  into  false  or  transverse  dehiscence,  called  Circumscissile,  is  well 
displayed  by  Figs.  325,  32G,  and  320,  viewed  in  the  order  named,  all 
illustrations  of  closely  related  plants.  A  very  curimis  form  of  special 
dehiscence  is  that  of  Jeffersonia  (Fig.  327). 

Rupturing. — Dehiscence  is  not  the  only  method  by  which  fruits 
open  to  discharge  their  seeds.  Rupturing  fruits  are  those  which  oj)en 
by  an  irregular  line. 

Dehiscence  by  Pores. — Some  portion  of  a  pericarp  may  decay  quickly, 
leaving  an  opening,  or  the  same  result  may  be  secured  by  excessive 
shrinkage  in  drying  of  the  more  delicate  tissue  of  some  part  of  the 
Pericarp,  as  in  Fig.  328.  Openings  of  this  kind  are  called  Pores.  Our 
consideration  of  this  subject  will  close  with  an  illustration  of  the  fruit  of 
the  Bcrtholctia,  or  Brazil-nut  (Fig.  324).  The  apex  of  this  enormously 
thickened  and  strongly  hardened  pericarp  consists  of  a  small  circular 
portion  coiniected  with  the  remainder  by  a  circle  of  tissue  which  quickly 
decays,  making  the  former  removable  as  a  plug  and  thus  leaving  an 
apical  pore. 


CHAPTER    XI 

CLASSIFICATION  OF  FRUITS 

A  PERFECT  or  even  fairly  satisfactory  classification  of  fruits  has  never 
been  presented,  and  this  is  impossible,  except  through  a  complete 
revision  and  uniform  agreement  of  terminology,  based  upon  a  uniform 
set  of  principles.  A  classification  of  some  sort  is,  however,  an  essential 
in  pharmaceutical  botany,  and  such  an  one  is  here  presented  as  appears 
most  serviceable  to  those  for  whom  it  is  intended. 

Two  Principles  Involved. — Among  all  the  various  systems  which  have 
been  proposed,  two  fundamental  principles  have  been  observed — first, 
the  morphological  structure;  second,  the  physiological  features.  By  the 
first,  fruits  have  been  classed  according  to  the  character  and  number 
of  the  parts  entering  into  their  formation  and  the  modifications  which 
these  have  undergone  in  fructification;  by  the  second,  according  to  the 
structural  and  functional  characters  as  seen  in  the  complete  fruit, 
without  regard  to  their  mode  of  origin.  As  characters  of  the  latter 
kind  exist  for  the  sake  of  the  offices  which  they  are  to  fulfil,  it  is  clear 
that  physiology  forms  the  basis  of  the  latter  method  of  classification. 
Although  it  is  impracticable  to  follow  either  system  without  some  regard 
to  the  other,  it  may  be  said  that  to  follow  in  the  main  the  morphological 
plan  is  the  more  scientific,  the  other  the  more  convenient  and  the  more 
practical,  especially  in  economic  work.  The  latter  is,  therefore,  the  plan 
which  is  here  adopted.  Fruits  possessing  pericarps  fitted  for  transpor- 
tation (a  of  our  table)  will  then  form  the  first  of  our  two  classes,  while 
those  fitted  for  discharging  their  seeds  i'??.  situ  upon  maturity  will  form 
the  second  {e  of  the  table). 

F'or  a  few  fruits  not  readily  introduced  to  this  key,  and  for  some 
exceptions,  the  explanations  which  follow  may  be  consulted: 

Fruits  with  pericarp  designed  for  transportation  (a). 

Fruits  with  pericarp  not  designed  for  transportation  (e). 
f   With  fleshy  pericarp  (Carnose)  (b). 
(    With  non-fleshy  pericarp  (Siccose)  (c). 
[   With  seeds  embedded  in  a  soft  endocarp  (g). 
\   With  seeds  enclosed  in  a  putamen  (h). 


nvo  I'lilXCIPLES  INVOLVKI)  ]]? 

f    With  ;m  (Midosiiig  involucre,  at  least  hcforc  maturity  (/). 

(    Without  an  enclosintj  iiixolucre  [d].* 

\    AVrticall\-  (JixisiMc  in  onc-sccdcd  j)arts  (/). 

I    A  one-set'ded  ]);irt  resulting  from  such  division  (j). 

I    Transversely  divisible  into  one-seeded  joints  (n). 

Not  divisible  into  one-seeded  ])arts  nor  the  produet  of  such 
I        di\-ision  (/,•). ^ 
Not  transversely  dehiscent  (/). 
Transversely  dehiscent  (f/). 
Monocarpellary  (?»)• 

Dicarpellary,  the  valves  sei)arating  from  the  placentae  (o). 
I    Not  monocarpellary  nor  dicarpellary,  with  valves  separating 
[       from  placentae  {y). 

r   Soft  throughout Berrv. 

•j'    With  a  soft,  tough  rind Hesperidium. 

I   With  a  hardened  rind Pepo. 

^    Putamen  of  bony  hardness;  solitary Drupe. 

Putamen  of  bony  hardness;  one  of  several  which  are 

coherent Pvrene. 

Putamen  of  bony  hardness;  one  of  many  which  are 

non-coherent Drupelet. 

Putamen  thin  and  tough Pome. 

Schizocarp 

(If  dicarjx'llary,  with  a  cari)ophore   ....        Cremocarp). 

Part  of  a  cremocar]j ]\Iericarp. 

Not  part  of  a  cremocarp   .      .      .      .Coccus,  Xucula,  or  Nutlet. 
Dehiscent,  the  vahes  separating  from  the  two 

placentae :\Iost  Silicles. 

With  thin,  winged  pericarp Samara. 

With  inflated  pericarp Utricle. 

Pericarp,  thickish  in  view  of  its  size,  not  inflated, 

sometimes  winged Akene. 

r   A  non-glumaceous  involucre,  with  contents  (dans. 

I    A  one-seeded  fruit  from  a  glans Kut. 

I    A  glumaeeous  involucre  with  contents    .      .      .  A  few  Spikelet.s. 

I    A  one-seeded  fruit  from  a  spikel(>t Caryopsis. 

f    Dehiscing  by  one  suture  only Follicle. 

I    Dehiscing  by  both  ventral  and  dorsal  sutures   .      .         Legume. 
I    (When  spirally  coiled ("ochlea). 

Exceptions  occur. 


118  CLASSIFICATION  OF  FRUITS 

n    .        Loment. 

^    I    Elongated Silique. 

I    Short Some  Silicles. 

y Capsule. 

q Pyxis. 

The  fact,  as  stated  above,  that  custom  has  not  been  uniform  in  the 
application  of  the  principles  of  classification  leading  to  the  above  terms, 
so  that  the  latter  are  not  employed  in  the  same  sense  in  different  botan- 
ical writings,  renders  it  necessary  that  such  a  key  as  that  presented 
should  be  supplemented  by  a  detailed  consideration  of  the  limitations 
and  modifications  of  each  class  of  fruits. 

The  Berry  (Figs.  281  and  310). — A  fruit  with  a  pericarp  fieshy  through- 
out, with  the  exception  of  the  epicarp.  Good  illustrations  are  the  grape 
and  the  belladonna.  In  these,  the  fruit  contains  little  or  no  cavity 
and  the  seeds  are  embedded  in  a  soft  pulp.  This  is  the  typical  form, 
from  which  we  see  a  variation  in  the  Tomato,  in  the  direction  of  a 
central  cavity,  which  in  the  Capsicum  becomes  complete.  The  latter  is 
frequently  called  a  capsule  and  connects  the  berries  with  the  latter 
class,  but  it  is  more  properly  grouped  with  the  berries.  A  similar 
modification,  though  more  slight,  is  found  in  the  checkerberry  (Fig.  303) 
and  the  cranberry.  The  term  has  also  been  applied  to  the  pomegranate 
and  similar  fruits,  but  these,  however  soft  within,  possess  a  distinctly 
hardened  exocarp  and  are  not  true  berries.  As  will  be  seen  farther  on, 
comparatively  few  of  the  fruits  which  are  designated  as  berries  in 
common  parlance  are  really  such.  The  berry  may  possess  one  or  more 
cells. 

The  Hesperidium  (Fig.  329) . — A  berry-like  fruit  with  a  soft,  but  tough 
rind.  The  term  has  never  been  applied  to  other  fruits  than  those 
related  to  the  orange  and  lemon.    They  are  several-celled. 

The  Pepo  (Fig.  332). — A  berry-like  fruit  in  structure,  usually  hollow 
and  with  an  indurated  rind.  It  is  one-celled.  Good  illustrations  are 
the  pumpkin  and  melon,  and  the  application  of  the  term  is  by  most 
authors  restricted  to  the  fruits  of  that  family  (the  Ciicurbitaceae) ; 
but  it  is  entirely  proper  to  extend  it  to  such  very  similar  fruits  of  other 
families  as  the  Calabash  (in  the  Bignoniaceae)  and  the  Pomegranate 
(in  the  Punicaccae). 

The  Drupe  or  Stone  Fruit  (Fig.  333). — A  fruit  with  a  sarcocarp  and 
epicarp  and  a  single  thick  bony  putamen.  Although  typically  one-celled 
and  one-seeded,  the  term  is  applicable  to  similar  fruits  with  several 


THE  SCIIIZOCARP 


119 


cells  all  enclosed  in  a  single  sarcocarp,  bnt  each  seed  possessing  its  own 
putaiuen.  Each  jiiitamen  with  its  own  seed  is  then  called  a  Pyrena  or 
Pyrene.  Familiar  illustrations  of  the  tyi)ical  drupe  among  medicinal 
plants  are  the  ])rune,  sumach  and  pepper,  and  of  the  several-celled 
form  that  of  the  RJiamnus,  (Fig.  331)  and  the  Phytolacca.  As  in  most 
classes  of  fruits,  we  find  liere  a  gradation  into  other  classes,  most  com- 
monly into  the  Schizocarp.  A  peculiar  fruit,  in  its  general  structure 
related  to  the  drupe,  is  the  so-called  legume  of  the  tamarind,  which 
possesses  an  exocarp  similar  to  that  of  a  pepo,  a  distinct  edible  sarco- 
carp and  a  crustaceous  endocarp  or  putamen  containing  several  seeds 
(Fig.  307). 


J^^. 


33X. 


JJJ. 


Fig.  329.  The  hesperidium  (lemon).  330.  Sehizocarp  of  Urena.  331.  Compound  drupe,  with 
detached  pyrena,  of  Rhamnus.  332.  Transverse  section  of  a  pepo.  333.  The  drupe  (plum).  334. 
Dicarpellary  sehizocarp  of  Labiatae. 


The  Psrrena  (Fig.  331).- — (Already  considered  under  Drupe.) 

The  Drupelet  (Fig.  305,  a). — Diifers  from  the  Fyrcna  in  that  it  pos- 
sesses not  only  its  own  separate  putamen,  but  a  sei)arate  sarcocarp  as 
well.  It  is  one  of  many  small  (Irui)es  belonging  to  an  aggregate  or 
multiple  fruit. 

The  Pome  (Fig.  308). — A  fleshy  fruit  with  a  tliin  chartaceous  or  cartil- 
aginous putamen.  It  is  several-celled.  The  term  is  commonly  restricted 
to  fruits  related  to  the  ai)i)le. 

The  Sehizocarp  (Figs.  2SS,  3.'>0,  and  334). — The  typical  sehizocarp 
should  be  delined  as  a  fruit  which  divides  septicidally  at  maturity  into 
one-seeded  carpels.  Because,  however,  schizocarps  frequently  vary  in 
the  constancy  and  completeness  with  which  they  undergo  this  process, 
they  are  defined  as  "divisible,"  rather  than  "dividing."  There  are, 
moreover,  cases  in  which  they  divide  into  one-seeded  ])arts  of  cari)els. 
The  comprehensive  definition,  therefore,  should  be  "dry  fruits  septi- 


120  CLASSIFICATION  OF  FRUITS 

cidally  divisible  at  maturity  into  one-seeded  parts."  Schizocarps  are 
commonly  provided  with  appendages  for  wind-transportation  or  for 
transportation  by  mechanical  adhesion  to  passing  bodies.  Those  forms 
which,  as  above  stated,  are  intermediate  toward  drupes  are  to  be 
classed  in  one  or  the  other  class,  according  to  whether  such  appendages 
for  distribution,  or  that  of  an  edible  pericarp,  is  the  more  pronounced. 
Even  schizocarps  which  are  not  cremocarps  may  possess  a  carpophore, 
as  in  geranium,  though  commonly  they  do  not. 

The  Cremocarp  (Figs.  247  and  288). — A  di-carpellary  schizocarp,  the 
carpels  attached  toward  their  summits  to  a  slender  carpophore,  from 
which  they  usually  only  incompletely  separate  at  maturity.  The  term 
is  restricted  to  the  fruits  of  the  UmbeUiferae.  They  are  commonly 
provided  with  appendages  for  fixation  to  passing  bodies,  frequently 
for  wind-transportation,  and  not  rarely  combine  these  two  methods 
of  distribution.  {Coniiim,  Celery,  etc.)  There  is  no  class  of  fruits  which 
possesses  a  greater  importance  in  pharmacy,  and  hardly  any  whose 
histological  features  are  of  greater  interest.  The  plane  of  separation  is 
called  the  Commissure,  a  term  applicable  to  a  similar  plane  in  other 
fruits.    (See  Mericarp.) 

The  Coccus,  Nucula,  or  Nutlet  (Fig.  330,  a,  and  Fig.  334,  a).— One  of 
the  divisions  of  a  schizocarp,  and  its  nature  has  been  explained  in  con- 
sidering that  group.  The  term  nutlet  is  commonly  applied  when  the 
pericarp  is  hard  and  close  to  the  seed. 

The  Mericarp  (Fig.  247,  either  half). — One  of  the  halves  into  which  a 
cremocarp  is  divisible.  Occasionally  they  are  self-separating  at  matur- 
ity, but  usually  only  incompletely  so.  They  are  one-seeded  and  possess 
a  completely  adnate  calyx  and  disk.  The  pericarp  almost  uniformly 
possesses  external  appendages  in  the  form  of  five  or  nine  ribs,  as  is  well 
shown  in  cross-sections  (Fig.  335,  h).  When  nine,  they  are  commonly 
of  two  forms,  alternating  with  one  another.  A  part  or  all  of  them  are 
much  subject  to  extension  into  variously  appendaged  or  pinnatifid 
wings  (Fig.  336,  a).  Internally,  the  mesocarp  is  almost  uniformly 
traversed  upon  both  the  faces  and  the  backs  of  the  carpel  by  tubes 
called  Vittae  (Fig.  335,  a),  commonly  with  suberous  walls  and  filled 
with  volatile  oil.  The  dorsal  vittae  alternate  in  position  with  the  ribs. 
Upon  thin  transverse  sections  these  oil-ducts  or  vittae  appear  as  per- 
forations, and  as  to  their  number  and  position  serve  the  most  important 
purposes  in  diagnosis  and  identification,  as  do  also  the  ribs.  These 
fruits  are  dorsally  compressed  when  broader  from  right  to  left  (Fig. 
336),   laterally  compressed  when  broader  in  the  opposite  direction. 


THE  AKENE  OR  ACHEMUM 


121 


IMericarps  are  of  three  classes:  (I)  The  Coelospermous,  characterized 
by  the  possession  by  the  seed  of  a  concave  face  (Fi^'.  '.VA7,  a);  (2)  the 
Caiiii)yIosi)ernK)iis,  characterized  by  the  ])()ssessi()n  of  a  loiigitiuHiially 
grooved  face  (Fig.  .'i'iS,  a);  and  (3)  the  Ortliospermous,  possessing  a 
plane  face  (Fig.  '.V.]P>). 

The  Silicle.     (See  Sili(nie.) 

The  Samara.—  All  iiulciiiscent  fruit  witli  a  winged  i)cricarp.  "^I'liey 
are  commonly  one-seeded,  as  well  as  one-carpel  led,  but  may  be  more. 
Typically,  it  is  the  ovarian  wall  or  the  tube  of  an  adnate  calyx  which 
develops  the  wing,  but  there  is  no  reason  why  the  term  should  not  be 
extended  to  include  similarly  transportable  fruits  with  wings  consisting 
of  the  accrescent  limb  of  a  calyx  (Figs.  288  and  289),  or  corolla  (Fig.  291), 
or  a  surrounding  alate  bract  (Fig.  292).  Commonly  the  samara  possesses 
but  a  single  wing,  unilateral,  as  in  the  ash  (Fig.  3.')9),  or  circular,  as  in 
the  elm  (Fig.  287),  but  not  rarely  more  than  one  wing  is  present,  as  in 
the  maple  (Fig.  340),  or  many  Malpighiaceae  (Fig.  342). 


—-a 


337 

Kig.  335.  Transverse  section  of  an  orthosperinous  niericarp: 
pressed  mericarp,  two  of  tlu>  ribs  winged.  337.  Coelospermous 
spermous  mericarp  of  Conium. 


33<S. 


vitta;   6,  rib.     330.     Dorsall.v  o( 
L-riearp  of  coriander.     33S.   Camp: 


The  Utricle  (Fig.  341). — A  one-seeded  indehiscent  fruit,  the  seed 
enclosed  in  a  thin,  bladdery  or  inflated  pericarj).  It  is  commonly  one- 
celled,  but  occasionally  several-celled.  Ordinarily,  utricles  eventually 
become  irregularly  rujjtured,  l)ut  in  a  few  forms  there  is  a  regular 
ventral  opein'ng,  ap])r()aching  toward  dehiscence. 

The  Akene  or  Achenium  (  Figs.  71  to  NO  and  ;M  1).  A  small,  indehiscent. 
one-seeded,  seed-like  fruit,  the  pci'icnrp  soiiicw  liat  thickened  and 
entirely  distinct  from  the  (Miclo.scd  seed.  The  aki-ne  varies  in  many 
directions  toward  other  fruits.  In  many  cases  the  pericarp  is  inclined 
to  be  flesln-  and  in  a  few  it  tends  toward  dehiscence,  thus  sinuilating  a 


122 


CLASSIFICATION  OF  FRUITS 


follicle.  Some  forms  of  the  akene  are  distinctly  winged,  so  that  they 
might,  but  for  the  relationship  of  the  species  yielding  them  to  akene- 
producing  species,  be  with  equal  propriety  classed  as  samaras.  They  are 
in  nearly  all  cases  provided  with  some  means  for  securing  wind-trans- 
portation or  for  attaching  themselves  to  passing  bodies,  and  yet  there 
are  numerous  cases  in  which  such  appendages  have  become  entirely 
obsolete.  For  these  reasons,  it  becomes  a  matter  of  extreme  difficulty 
to  frame  a  definition  at  once  comprehensive  and  delimiting  fpr  this 
group.  The  inferior  akene  is  sometimes  distinguished  bj^  the  term 
Cypsela  (Figs.  74  to  80). 


Fig.  339.  Samara  of  ash.  340.  Of  maple.  341.  Utricle.  342.  Several  winged  samara  of  Mascaffraia. 
343.  Vertical  section  of  anthodium.  344.  Vertical  section  of  akene  of  buttercup.  345.  Same  of  the 
glans  of  black  walnut.    346.  Glans  of  Fagus,  or  beech-nut. 


Note  should  here  be  taken  of  the  fact  that  the  latter  is  characteristic 
of  the  largest  of  all  families,  the  Compositae,  in  which  the  akenes  of 
the  head  are  massed  and  partially,  or  sometimes  completely,  surrounded 
and  enclosed  by  an  involucre,  the  whole  constituting  a  multiple  fruit  to 
which  the  name  Anthodium  (Fig.  343)  has  been  applied.  The  anthodium 
varies  greatly  in  its  character.  Although  usually  many-flowered,  it  is 
commonly  few-,  or  even  in  rare  cases,  one-flowered.  In  those  cases  in 
which  the  involucre  completely  encloses  the  akenes,  it  is  commonly 
appendaged  for  distribution  in  an  entire  condition,  as  in  the  burdock. 
This  condition  connects  the  anthodium  with  the  glans  and  the  contained 
achenium  with  the  nut.  Indeed,  it  is  almost  impossible  to  distinguish 
structurally  between  fruits  representing  these  two  classes,  as,  for  instance, 
those  of  Xanthium  and  Fagus. 

The  Glans  (Figs.  345  and  346). — A  fruit  consisting  of  an  accrescent 
and  partially  or  (commonly)  completely  enclosing  involucre  containing 


THE  LEGUME  123 

one  or  more  nuts.  The  involucre  may  be  dehiscent,  as  in  the  chestnut 
and  hickory-nut,  or  indehiscent,  as  in  the  black  wahuit  (Fig.  345).  In 
some  of  its  forms,  the  involucre  of  the  glans  tends  to  become  fleshy. 
Inasmuch,  however,  as  the  design  of  such  pseudo-flesliy  pericarps  is 
not  that  of  subserving  transportation  by  their  f(K)d-])r()i)erties,  they  are 
more  appr()i)riately  regarded  as  non-fieshy.  Wliile  dcjKMiding,  Hke  the 
grasses,  upon  their  gregarious  habits  for  perpetuation,  nut-yielding 
plants  are  apparently  in  many  cases  distributed  by  the  rounded  form  of 
their  coats  and  the  readiness  with  which  they  are  transported  bj^  flowing 
water. 

The  Nuca  or  Nut  (Figs.  345,  a,  and  340,  a). — The  relationship  of  the 
nut  and  its  glans  to  the  akene  and  its  anthodium  has  already  been 
pointed  out.  The  nut  is  in  all  cases  much  larger  than  the  akene  and  its 
pericarp  commonly  much  thickened  and  very  hard. 

The  Spikelet  (Fig.  347). — A  fruit  possessing  a  glumaceous  involucre 
and  pertaining  to  the  Gramineae  (grass  family)  and  related  orders. 
This  class  of  fruits,  like  the  glans  and  nut,  connects  those  fruits  which 
are  adaj^ted  to  transportation  with  those  which  are  not.  Although, 
in  general,  these  plants  depend  for  their  perpetuation  upon  a  highly 
gregarious  habit  rather  than  upon  provisions  for  distribution  of  their 
fruits,  yet  the  spikelets  of  some  grasses  are  unmistakably  so  designed, 
and  are  transported  with  their  caryopses  enclosed  in  the  glurhes. 

The  Caryopsis  or  Grain  (Fig.  348). — A  seed-like  fruit  produced  in  a 
spikelet,  the  oxarian  wall  and  the  seed-body  closely  adnate. 

The  FoIUcle  (Fig.  349). — A  monocarpellary  fruit  dehiscing  by  one 
suture  only,  this  the  ventral,  except  in  rare  cases. 

The  Legume  (Fig.  350). — A  monocarpellary  fruit,  non-fleshy  and 
dehiscing  by  both  ventral  and  dorsal  sutures.  Notwithstanding  the 
definition  thus  given,  we  have  to  record  the  fact  that  in  accordance  with 
a  different  principle  and  construction,  the  title  includes  all  fruits  of  the 
natural  order  Leguminosae.  It,  therefore,  becomes  necessary  to  point 
out  that  the  fruits  of  this  family  are  extremely  variable,  and  this  in 
directions  which  frequently  carry  them  widely  away  from  both  the 
structural  and  the  physiological  characters  of  the  legume.  The  pecu- 
liarities of  the  tamarind  have  already  been  pointed  out.  In  the  fruit 
of  the  Inga  the  dehiscent  legume  is  filled  with  a  large  amount  of  juicy, 
edible  pulp,  in  which  the  seeds  are  embedded.  In  other  species  this 
pulp  is  replaced  by  one  of  a  powdery  consistency,  while  in  others  it  is 
fleshy  or  subcorneous.  A  great  many  legumes  of  this  family  are  not 
only  indehiscent,  but  winged  and  one-seeded,  and  thus  are  true  samaras. 


124 


CLASSIFICATION  OP  FRUITS 


The  fruit  of  tlie  Dipteryx  is  one-seeded  and  is  dehiseent,  but  the  peri- 
carp is  enormously  thickened  and  first  flesliy,  then  spongy.  That  of  the 
Cassia  Fistula  lias  its  seeds  enclosed  in  a  pulp  and  partly  separated  from 
one  another  by  transverse  septa.  It  is  thus  apparent  that  many 
legumes  pertain  to  our  first,  rather  than  to  our  second,  division. 


'•^SZ 


'3S4. 


3SS. 


JS6. 


Fig.  347.  Spikelet  of  a  grass.  348.  Caryop.sis  from  last.  349.  Follicle  of  Asclepias.  350.  Legume 
of  pea.  351.  Loment  of  Aeschynomene.  352.  Loment  of  Sophora.  353.  Cochlea  of  Prosopis.  354. 
Silique  of  Cardamine.  355.  Silicle  of  Aethiomena.  356.  Silicle  of  Hexaptera.  357.  Silicle  of  Succowia. 
358.  Capsule  of  poppy. 


Two  distinctive  forms  of  the  legume  have  become  dignified  by  the 
application  of  special  names,  as  follows: 

The  Loment  (Figs.  351  and  352)  is  a  leguminous  fruit  which  may  or 
may  not  be  dehiscent,  but  which  is  separable  at  maturity  by  transverse 
divisions  into  one-seeded  parts.  In  the  Aeschynomejie  these  parts  are 
adapted  to  fixation  to  passing  bodies,  or  occasionally  also  much  flattened 
and  expanded  to  act  as  samaras.  In  the  Soyliora  (Fig.  352)  the  joints 
are  smooth,  hard  and  rounded,  and  highly  elastic,  so  that,  in  falling 
upon  the  stony  soil,  they  are  adapted  to  bounding  and  running  to  a 
considerable  distance.  The  term  loment  has  also  been  extended  to 
include  those  siliques  which  display  a  similar  character. 

The  Cochlea  (Fig.  353). — A  legume  which  is  spirally  coiled. 


THE  SYCONIUM 


125 


The  Silique  (Fifj.  354). — A  (li-('ar])cllary  deliiscent  fruit,  the  two  valves 
separating-  t'roiii  the  mar<^ins  of  tiie  phieentae  at  maturity,  leaving  the 
latter  attached  tt)  the  torus  and  to  a  false  septum,  whieh  divides  the 
siiicpie  into  two  ])arts.  The  ])riii(i{)al  modification  of  the  silique  proper 
is  into  the  loment-like  form  which  we  have  already  considered.  These 
loment-producing  ])lants  are  commonly  found  in  the  vicinity  of  water, 
and  their  fruits  are  adaj)ted  to  transportation  by  this  method.  A  more 
im|)ortaiit  modification  is  into: 

The  Silicle  (Fi^s.  'Ar>r^  to  357). — 'J'his  difVers  from  the  siH(iue  not  only 
in  being  short  and  broad,  but  in  possessing  ordinarily  some  form  of 
adaptation  to  wind  or  other  transportation,  thus  belonging  in  our  first 
class. 

The  Capsule  (Figs.  318  to  238).— The  typical  capsule  is  to  be  defined 
as  a  di-  to  polycarpellary  longitudinally  dehiscent  fruit.  From  the 
typical  form,  however,  it  varies  in  several  directions  to  such  a  degree 


SS^. 


J60. 


^6i 


<36Z 


Fig.  359.    Giilbalus  of  ./i/Nipcrus.     300.    Strobile  of   Picca.     3()1.    Strobile  of   hop.     302.    Syconium  of 
fig.     303.   Pyxis  of  henliano. 

as  to  render  it  impossible  to  frame  a  perfect  definition.  The  capsule 
of  the  poi)py  (Fig.  358)  opens  by  a  number  of  small  pores  at  the  summit, 
and  this  is  true  of  many  other  forms.  In  other  cases  the  mode  of  opening 
is  by  various  forms  of  irregular  dehiscence  intermediate  between  the 
longitudinal  and  tlic  circumscissile.  Finally,  w(>  must  note  that  many 
fruits,  like  those  of  some  species  of  Passljlord,  which  possess  no  regular 
or  natural  method  of  ()i)ening,  are  still  classed  as  ca])sules  by  systematic 
botanists. 

The  Pyxis  (Fig.  :!().')). — A  circumsci.ssily  dehiscent  fruit. 

The  Syconium  (Fig.  302). — A  fruit  consisting  of  a  hollow  branch, 
becoming  fleshy,  its  inner  surface  the  recejitaclc  for  many  >niall, 
one-seeded,  akcnc-likc  fruits. 


126  CLASSIFICATION  OF  FRUITS 

The  Aeterio  (Figs.  304  and  305). — An  aggregate  fruit,  with  an  accres- 
cent fleshy  torus  and  many  crowded  pistils. 

The  Strobile  (Figs.  360  and  361). — A  multiple  dry  fruit,  its  elements  in 
the  form  of  imbricated  scales. 

The  Galbalus  (Fig.  359).— A  fruit  similar  to  the  last,  but  the  scales 
fleshy  or  much  thickened  above,  so  that  the  form  becomes  more  or 
less  globular. 

In  conclusion,  it  may  be  remarked  that  to  assign  a  name  to  a  fruit 
is  insufficient  in  most  cases,  especially  in  those  of  aggregate  and 
multiple  fruits,  to  designate  its  character. 


CHAPTER    XII 
THE  SEED 


Changes  in  the  Ovule. — As  in  the  case  of  the  parts  entering  into  the 
formation  of  the  pericarp,  so  in  that  of  the  part  forming  the  seed — 
namely,  the  ovule — it  is  well  to  precede  our  study  of  the  changes  which 
it  undergoes  by  a  consideration  of  the  objects  to  be  attained  thereby. 

Development  of  the  Embryo. — 
The  essential  feature  of  the  seed  is 
the  possession  as  one  of  its  parts 
of  a  more  or  less  rudimentary 
plant,  developed  from  the  fertil- 
ized oosphere,  and  known  as  the 
Embryo,  and  capable  of  remaining 
for  a  more  or  less  extended  period, 
before  germination,  in  a  state  of 
suspended  animation. 

The  development  of  the  embryo 
commences  with  the  division  of 
the  fertilized  oosphere  into  two 
cells,  each  of  which  grows  and 
becomes  capable  of  itself  dividing 
similarly.  The  result  of  such  cell- 
propagation  is  the  production  of 
a  tissue  and  of  a  body  which 
becomes  elongated  through  suc- 
cessive transverse  divisions  of  its 
cells,  or  certain  of  them,  and 
broadened  by  their  longitudinal 
division.  Several  progressive  forms  reached  by 
this  ])r()cess  arc  sliown  in  Figs.  305  to  3()8. 

Provisions  Required  by  the  Embryo. — During  the  period  intervening 
between  the  beginning  and  the  completion  of  seed-formation  the 
embryo  requires  nourishing,  and  provisions  for  this  constitutes  the  first 
requirement  of  the  process.     The  further  development  and  growth  of 


J66. 

Figs.  364  to  368.  Figures  illustrating  develop- 
ment of  the  embryo;  the  vertical  chain  of  cells  is 
the  pro-embryo,  the  uppermost  of  them  becomes 
the  caulicle  and  the  enlargement  the  cotyledons. 


the 


ibr' 


(hi 


ring 


128  THE  SEED 

the  embryo,  between  the  time  of  germination  and  that  of  absorption  by 
it  from  the  external  world,  calls  for  additional  nourishment.  This  can 
be  met  only  by  the  storage  as  a  part  of  the  seed  of  an  additional  food- 
supply. 

Protection  of  the  seed-contents  during  its  development  is  only  partially 
afforded  by  the  pericarp,  and  this  office  is  supplemented  by  the  coverings 
of  the  seed  itself,  while  its  similar  self-protection  between  the  periods  of 
maturity  and  germination  is  a  manifest  necessity. 

The  transfer  of  the  mature  seed  to  the  point  of  germination,  or  its 
dissemination,  and  its  fixation  in  a  favorable  site,  have  already  been 
referred  to.  We  have  seen  that  in  many  cases  these  offices  are  not 
provided  for  by  the  pericarp,  and  we  must  look  for  such  provision  to 
the  seed  itself. 

Parts  of  a  Seed. — The  parts  of  the  seed  by  which  these  several  offices 
are  performed  we  find  to  be  as  follows: 

The  Perisperm.- — The  source  of  food-supply  during  the  germination 
of  the  macrospore  and  development  of  the  gametophyte  we  have  seen 
to  be  the  portion  of  the  nucellus  external  to  the  embryo-sac.  Usually 
more  or  less  of  this  material  remains  during  at  least  the  earlier  period  of 
the  development  of  the  embryo  and  contributes  to  the  nourishment 
of  the  latter.  Occasionally  it  persists  even  in  the  seed  condition.  It  is 
then  known  as  the  Perisperm. 

The  Endosperm. — Inside  the  embryo-sac  a  further  store  of  nutriment 
is  caused  to  develop  as  a  result  of  fertilization,  this  constituting  the 
chief  supply  of  the  growing  embryo.  More  or  less  of  this  also  may 
persist,  and  usually  does,  upon  the  maturity  of  the  seed.  It  is  known  as 
the  Endosperm. 

Albuminous  and  Exalbuminous  Seeds. — As  the  embryo  develops,  it 
stores  within  its  own  body  more  or  less  nutriment.  At  maturity  we 
may  find  that  the  entire  store  of  nutriment  has  thus  been  transferred 
to  the  body  of  the  embryo,  and  the  seed  is  said  to  be  Exalbuminous,  or 
we  may  find  more  or  less  endosperm  or  perisperm,  or  both,  when  the 
seed  is  said  to  be  Albuminous,  and  this  external  nourishment  is  known 
as  the  Albumin.  In  only  a  few  seeds  used  in  medicine  does  the  albumin 
consist  in  any  part  of  perisperm.  The  chemical  nature  of  the  albumin 
is  extremely  variable.  It  received  its  misleading  name  because  of  the 
similarity  of  its  function  to  that  of  the  albumin  of  the  egg. 

Protection. — Protection  to  the  embryo  may  be  afforded  by  the  albumin 
when  that  is  of  the  required  consistency  or  composition,  the  conditions 
of  the  latter  being  a  mere  parallel  of  those  already  considered  under 


77/ A'   IIIU'M  129 

tlic  siil)j(>ct  ol"  the  pericarj).     Moi-c  IVcciiuMitly,  Iiowcxcr,  it  is  -ccurt'd 
(Mitircl\'  tlir()iiii;li  the  coats  of  tlit'  seed. 

The  Scrd-codf.s. — Those  may  con-csijoiid  to  the  coats  of  the  o\ul(', 
though  usually  tiie  i)riiniiie  is  found  to  have  (lisa])])('ar('d.  When  it 
persists  it  takes  the  name  of  Tegmen,  or  Endo])leura,  the  secundine 
hecomino;  the  Testa,  or  Exopleura.  Rarely  tlie  secundine  also  disa])i)ears 
and  the  seed  is  Naked.  The  seed  will  also  be  naked  when  ])roduced  from 
a  naked  ovule. 

Tlir  Micropiilc. — When  one  or  both  of  the  coats  persists,  the  point 
where  the  foramen,  now  closed,  existed  becomes  the  Micropyle. 

The  Aril. — Frecjuently  the  develoi)ment  of  a  new  coat  external  to 
the  others  is  induced  by  fertilization,  and  this  is  known  by  the  general 
name  of  Aril.  If  it  develop  from  the  chalaza  or  a  lower  point,  it  is  called 
an  Arillus,  or  True  Aril;  if  from  the  micropyle,  an  Arillode,  or  False 
Aril. 

Dissemination. — The  provisions  of  the  seed  for  securing  dissemination 
are  in  most  res])ects  comparable  with  those  afi'ecting  the  pericarp. 
Wind-distribution  is  preeminent,  that  by  fixation  to  passing  bodies  is 
fre(iuent,  and  that  by  means  of  an  edible  coat  is  rare. 

Fixation. — The  fixation  of  seeds  disseminated  without  the  pericarp  is 
favored  by  their  small  size,  enabling  them  readily  to  enter  crevices  and 
cavities,  and  by  peculiarities  of  surface  which  fa\()r  the  same  process. 

The  large  number  and  importance  of  medicinal  seeds  lend  great 
importance  to  their  study  by  the  i)harmacogn()sist,  and  this  is  especially 
true  of  the  histology  of  all  their  ])arts.  Inasnnich,  however,  as  the 
subject  of  histology  has  been  referred  to  a  se})arate  ])ortion  of  the  work, 
we  shall  here  consider  only  such  characters  as  can  be  distinguished 
by  means  of  an  ordinary  lens. 

The  Hilum. — The  hiluni  is  in  most  cases  readily  perceptible,  but  is 
occasionally  found  only  by  minute  examination.  It  is  to  be  studied  as 
to  its  position,  size,  form,  surface,  and  color.  Its  position  is  sometimes 
fixed  with  reference  to  the  form  of  the  seed,  as  at  the  larger  or  smaller 
end,  upon  the  l)road  side  or  on  the  edge,  as  well  as  with  reference  to  the 
micropyle,  adjoining  it,  at  the  ()])posit(>  end  or  at  some  intermediate 
])oint.  It  is  the  last-mentioned  character  which  detennines  the  class 
of  seed  as  to  itstr()])ism  (see  Ovule).  In  size  the  liiluni  may  b(>  a  slight 
point,  or  it  may  cover  a  considerable  jjortion  t)f  the  surface.  Its  form  is 
frequently  characteristic,  as  heart-shaped  (Fig.  '.M())  or  lim-ar  and 
channelled,  as  in  Fig.  '.Vi\.  Its  color  fre(iuenlly  (lifV(>rs  markedly  from 
that  of  the  remainder  of  the  seed. 


130 


THE  SEED 


The  Raphe. — The  raphe,  extending  from  the  hihim  to  tlie  chalaza 
when  these  do  not  coincide,  is  ordinarily  not  readily  perceptible  upon 
the  surface.  When  it  is  so,  as  in  Figs.  372  and  373,  its  appearance  is  of 
great  diagnostic  value  and  must  be  closely  scrutinized.  The  chalaza 
in  its  simple  form  calls  for  lio  special  attention. 

The  Strophiole. — If,  however,  an  enlargement  appears  at  this  point 
(the  Stroyliiole,  Fig.  374,  a),  it  must  not  be  overlooked.  The  strophiole 
may  develop  into  the  arillus  (Fig.  375),  a  partial  or  complete  covering, 
and  its  characters  call  for  the  same  attention  which  is  requisite  for  the 
testa. 


JM        <^^J 


Fig.  369.  Vertical  section,  seed  of  Cardamomum.  370.  Cordate  hihiin,  of  Cardiospermum.  371. 
Linear  hilum  of  Calabar  bean.  372.  Central  hilum  of  nux  vomica.  373.  Seed  of  Niederlinia  with 
conspicuous  raphe  and  funiculus.  374.  Seed  of  Hypericum  with  large  strophiole  at  a.  375.  Seed  of 
Hanetic  with  partial  arillus.  376.  Pitted  seed  of  Sanvegesia.  377.  Reticulate  seed  of  henbane.  378 . 
Reticulate-pitted  seed  of  tobacco.  379.  Finely  reticulated  seed  of  Datura.  380.  Seed  of  Ricinus, 
with  caruncle  at  a.  381.  Arilled  seed  of  Myrislica.  382.  Seed  of  Acorus,  with  peculiarly  appendaged 
micropyle. 


The  Testa. — The  testa  is  not  wanting  in  any  medicinal  seed.  In 
general  it  is  not  closely  adherent  to  the  underlying  tissue,  and  it  can 
be  readily  removed.  In  its  thickness,  consistency,  surface,  color  and 
appendages  it  yields  important  pharmacognostical  characters.  It  may 
be  pitted  (Fig.  370),  reticulate  (Fig.  377),  reticulate-pitted  (Fig.  378) 
or  hairy  (Fig.  372),  and  the  minute  characters  of  its  pits,  tubercles, 
ridges,  or  hairs  must  not  be  overlooked.  It  may  be  dull  or  shiny,  and 
its  color  may  be  uniform  or  variegated  (Fig.  379).  Its  luster  or  shade 
of  color  is  frequently  of  the  greatest  assistance  in  determining  the  age, 
freshness,  mode  of  preparing  or  preserving,  or  other  conditions  on  which 
the  comparative  medicinal  quality  of  the  seed  depends. 


THE   TEGMEN 


131 


The  Caruncle.-  Tlu>  ('iil;ir<;eiiu'iit  at  the  iiiicr()])yle  (tlic  Canmcle, 
Fig.  380,  a)  calls  for  the  same  scrutiny  as  the  str()i)hiole.  It  may  be 
variously  api)eM(la<j;ed  (Fig.  382),  and,  like  the  latter,  it  may  extend 
into  a  partial  or  com})letc  covering,  the  arillode.  The  arillus,  or  arillode 
(Fig.  381),  may  he  i)artial,  as  in  nutmeg,  or  complete,  as  in  the  seed  of 
the  Euonymus. 

Appendages. — Appendages  to  the  seed  do  not  always  take  the  form 
of  an  aril  of  either  class,  nor  is  their  origin  confined  to  the  points  from 
which  the  aril  devel()i)s.  Fither  as  aril  or  ai)i)endage  from  the  general 
surface,  they  exliibit  a  great  variety  of  form,  of  equal  importance  with 


,.« 


383. 


''''  iy?,si  ^^ 


J94.     '^os.  jm. 


-Wl 


JUO. 


JM 


Fig.  383.  Seed  of  Eiicharidiiim,  with  fringed  margin.  384.  Penicillate  seed  of  Epilobium.  385. 
Tufted  seed  of  Pelrocoptis.  386.  Finibriate-winged  seed  of  Daitais.  387.  Winged  seed  of  Cinchona. 
388.  Pluniose-awned  seed  of  Stroiihanthus.  389.  A  globose  seed.  390.  Lenticular  seed  of  Lens. 
391.  Saucer-shaped  seed  of  Lecanosperma.  392.  Linear  seed  of  Nepenthes.  393.  A  polyhedral  seed 
of  Nolina.  394.  Serrated  seed  of  Akebia.  395.  Reniforni  seed  of  bean.  39G.  Cochlear  seed  of  Ilelio- 
chnris.  397.  Crescent-shaped  seed  of  Menispermum.  398.  A  lobed  seed.  399.  Nutmeg,  with  the 
albumin  niniinutcd. 


those  which  characterize  the  pericarp.  Forms  of  especially  frequent 
occurrence  are  exhibited  by  Figs.  383  to  388.  Important  distinctions 
sometimes  exist  between  seeds  bearing  similar  ai)])endages,  as  regards 
the  j)oints  from  which  the  latter  originate,  as  in  the  case  of  strojihanthus, 
false  and  true. 

The  general  form  of  the  testa  is,  of  course,  that  of  the  seed,  and  calls 
for  terms  applicable  to  the  forms  of  solid  bodies  (Figs.  389  to  398). 

The  Tegmen. — The  tegmen,  when  present,  is  extremely  thin  and  tightly 
adiierent  to  the  nucellus,  following  closely  all  inequalities  upon  the 
surface  of  the  latter,  and  occasionally  having  its  intruded  folds  caught 
between   the   forming   masses   of    the   albumin    and    discernible   upon 


132 


THE  SEED 


section  of  the  latter  as  slender  veins,  giving  us  the  so-called  Ruminated 
Albumin  (Fig.  :599). 

The  Albumin. — The  albumin  is  characterized  chiefly  by  its  con- 
sistency, being  bony,  as  in  the  ivory  nut  and  date;  horny,  as  in  nux 
vomica;  oily,  as  in  the  castor-bean  and  cacao;  fleshy,  mealy,  etc.  In 
sectioning  the  seed,  note  should  be  taken  of  the  presence,  number, 
position  and  forms  of  any  cavities  which  may  exist  in  it. 

The  Embryo. — The  embryo  calls  for  the  most  thorough  and  minute 
study  as  a  basis  for  systematic  work,  though  for  the  pharmacognosist 
only  the  more  important  details  of  its  general  structure  need  be  con- 
sidered. It  has  already  been  stated  that  it  consists  of  one  or  more 
phytomers. 


4U2 


Fig.  400.  Circinate  embryo  of  Campoma^H'.sfVi:  /(,  radicle;  ca,  caulicle-  fo<,  cotyledons.  401.  Section 
through  seed  of  Gynocardia.  402.  Centric  curved  embryo  of  Gynocramhe.  403.  Centric  straight  embryo 
of  Frankeaia.  404.  Germinating  monocotyledonous  embryo.  405.  Embryo  of  Dipteryx  with  pinnatifid 
plumule  (pO-    406.  Polycotyledonous  embryo. 


The  Caulicle. — The  chain  of  cells  first  formed  is  the  pro-embryo,  and 
this  is  supposed  to  act  in  transferring  nourishment  to  the  embryo. 
At  its  end,  next  to  the  cotyledons,  develops  the  first  internode  of  the 
coming  plant,  and  this  becomes  the  caulicle  (m  in  Figs.  400  to  403), 
in  old  works  denominated  the  "radicle." 


POSITION  OF   THE  EMBRYO  133 

The  Radicle. — ^Tlie  Radicle  (//  in  the  last-iianu-d  (i<,nircs)  is  tlie  extreme 
tip  of  the  cauliele,  which  points  always  in  the  direction  of  the  micropyle. 
From  this  i)()int  the  root  is  to  be  developed.  The  embryo  may  consist 
of  nothing  fnrther  than  the  cauliele,  and  even  this  may  be  of  the  most 
elementary  character. 

The  Cotyledons. — Ordinarily,  however,  there  develops  at  the  node 
(tiie  point  opposite  to  the  radicle)  one  or  more  Cotyledons,  or  Seed- 
leaves  {cot  in  the  figures). 

Monocotyledons,  Dicotyledons,  and  Polycotyledons. — Most  seeds  which 
possess  but  a  single  cotyledon  (Fig.  404)  are  grouped  together  in  a 
division  of  the  Angiosperms,  which  for  this  reason  are  called  Mono- 
cotyledons, those  with  two  in  the  Dicotyledons.  A  few  plants,  mo.stly 
Gymnosperms,  are  ])()lyc()tyledons  (Fig.  406). 

The  Plumule. — The  highest  plants  of  their  respective  groups  develop 
a  second  phytomer  lying  between  the  cotyledons,  or  if  there  be  but  one 
cotyledon,  mostly  enwrapped  by  it.  This  is  the  Plumule  (Fig.  405,  jjI), 
which  shows  the  same  variation  in  the  degree  of  its  development  as 
that  which  characterizes  the  lower.  When  its  leaves  are  developed, 
they  bear  a  closer  resemblance,  as  in  the  figure,  to  the  mature  leaves 
of  the  plant  than  do  the  cotyledons,  following  out  the  law  referred  to  in 
our  introduction.  Among  dicotyledons,  the  ])lumulc  commonly  pertains 
to  exalbuminous  seeds. 

Direction  of  the  Radicle. — Terms  used  to  indicate  dirt'erent  directions 
of  the  radicle  refer  to  its  direction  with  relation  to  the  fruit,  its  direction 
in  relation  to  the  micropyle  being,  as  has  been  stated,  always  the  same. 
It  is  Ascending  when  it  points  toward  the  apex  of  the  fruit.  Descending 
when  in  the  opposite  direction,  and  Horizontal  when  intermediate. 
The  latter  form  is  Centrifugal  when  pointing  toward  the  perii)hery, 
Centripetal  when  toward  the  axis. 

Position  of  the  Embryo. — The  position  of  the  embryo  with  reference 
to  the  albumin  is  always  highly  cliaracteristic.  It  is  Axile  or  Centric 
when  in  the  center  of  the  albumin  (Figs.  402  and  403),  whether  straight 
or  curved;  Eccentric  when  within  the  albumin,  but  outside  of  its  center 
(Fig.  407);  Peripheral  when  1\  ing  upon  the  surface  of  the  albumin.  In 
the  latter  position  it  may  be  straight,  sim])ly  cur\ed  (Fig.  4()S\  or 
circinately  coiletl  (Figs.  409  and  410). 

The  relative  sizes  of  the  embryo  and  the  albumin  vary  from  those 
in  which  the  former  is  a  mere  sjjeck  in  a  large  mass  of  the  latter  to  that 
in  which  the  proi)ortions  are  reversed,  or  in  which  the  ;iil)uniin  is 
entirely  wanting. 


134 


THE  SEED 


Forms  of  the  Embryo. — The  eml)ryo  should  in  all  cases  be  dissected 
from  the  contiguous  parts  and  the  relations  of  its  parts  to  one  another 
made  out.  It  may  be  straight,  variously  curved,  crumpled  (Fig.  411), 
or  variously  folded.  In  the  latter  condition  the  radicle  may  be  brought 
into  juxtaposition  with  the  edges  of  the  cotyledons  (Accumbent,  Fig. 
413)  or  with  the  face  of  one  of  them  (Incumbent,  Fig.  412),  One 
cotyledon  may  enwrap  the  other  (Fig.  414).  When  a  single  cotyledon 
partly  encloses  the  greater  portion  of  the  remainder  of  the  embryo 
it  is  sometimes  called  the  Scutellum  (Fig.  415).  Some  of  the  terms 
applicable  to  the  consistency  of  the  albumin  are  also  applicable  to  that 
of  the  cotvledons. 


Fig.  407.  Eccentric  curved  embryo  of  Galium.  408.  Peripheral  simply  curved  embryo  of  Bosia.  409. 
Peripheral  circinately  curved  embryo  of  ^cAj/raniAes.  410.  Circinately  coiled  embrj'o.  411.  Crumpled 
embryo  of  Suaeda.  412.  Incumbent  radicle  of  Calepina.  413.  Accumbent  radicle  of  Megacarpaea. 
414.  Embryo  of  Dryobolanops,  one  cotyledon  enwrapping  the  others.  415.  Embryo  of  barley  with 
scutellum   (s). 

The  Taste. — Finally,  the  pharmacognosist  will  find  it  of  importance 
in  the  case  of  seeds  possessing  a  characteristic  taste  to  inform  himself 
as  to  the  part,  if  any,  to  which  such  taste  is  restricted. 

Reproduction  Completed. — With  the  production  of  the  seed,  containing 
a  distinct  living  individual  separated  from  the  parent  and  fitted  for 
independent  existence,  reproduction  can  strictly  be  considered  as  com- 
pleted, although  the  progeny  is  still  in  its  infancy  and  its  form  not  yet 
perfect. 

Similarity  of  the  Seed  to  the  Bud. — The  analogy  between  the  seed  and 
the  bud  is  apparent.  Each  consists  of  one  or  more  vegetative  units 
ready  to  develop  under  proper  conditions  into  a  perfect  semblance  of 
the  parent,  and  each  is  provided  with  a  store  of  prepared  nourishment 


EXAMINATION  OF   THE  SEED  135 

to  sustain  it  until  able  to  manufacture  such  for  itself.  The  distinction  is 
in  the  radically  different  modes  of  origin,  and  in  structure,  leading  to 
different  powers  of  reproduction. 

Examination  of  the  Seed. — ^In  the  examination  of  the  seed  for  the 
determination  of  the  {'haracters  above  defined,  the  most  certain  method 
is  the  examination  of  transverse  and  longitudinal  sections  by  the  use 
of  the  compound  microscope,  as  will  be  explained  in  Part  II  of  this 
work.  It  is  not  difficult,  however,  to  determine  all  the  essential  char- 
acters of  most  seeds  by  the  aid  of  an  ordinary  magnifying  glass.  The 
superficial  characters  of  the  seed  should  first  be  examined  in  the  dry 
condition,  after  which  it  should  be  thoroughly  soaked  for  a  period 
varying  from  a  few  hours  to  several  days,  or  the  preparation  may  be 
hastened  by  gently  boiling.  Its  superficial  characters  must  be  then 
again  examined  and  compared  with  those  previously  observed.  Espe- 
cially must  the  relative  positions  of  chalaza,  hilum,  micropyle,  and  raphe 
be  accurately  determined.  A  longitudinal  incision  is  then  to  be  made 
along  one  side  and  the  coats  removed,  separately  if  possible.  The 
examination  of  the  testa,  with  the  discovery  of  a  much  thickened  line, 
will  sometimes  disclose  a  raphe  which  was  overlooked  in  the  superficial 
examination.  In  removing  the  coats,  great  care  must  be  taken  to  avoid 
wounding  the  nucellus.  The  position  of  the  embryo  with  regard  to  the 
albumin,  if  any,  and  its  general  form  can  now  be  readily  ascertained. 
The  embryo  should  finally  be  removed  and  its  several  parts  studied. 
The  most  common  error  made  by  students  is  the  mistaking  of  small 
one-seeded  fruits,  such  as  mericari)s,  akenes,  and  nuculae,  for  seeds,  with 
the  result  that  all  of  the  parts  and  their  relations  are  confused.  The 
substitution  of  such  terms  as  conium-fruit,  coriander-fruit,  burdock- 
fruit,  and  hem])-fniit  for  the  incorrect  terms  "Conium-seed,"  etc.,  in 
common  use,  should  be  encouraged  by  all  educated  i)harmacists  in 
their  daily  business  relations,  as  a  correct  idea  of  the  natiu'e  of  the  jiarts 
employed  lies  at  the  foundation  of  a  proper  understanding  of  their 
composition  and  i)r()j)crties. 


CHAPTER    XIII 
GENERAL  STRUCTURE  OF   ROOT  AND  STEM 

The  Development  of  Different  Tissues. — The  de\'e]opment  of  the  stem 
commences  with  the  formation  of  the  embryo,  by  the  process  explained 
at  the  beginning  of  our  study  of  the  seed.  So  long  as  the  cells  produced 
by  this  process  are  the  same  in  kind,  the  body  consists  of  but  one  tissue; 
but  through  differentiation  and  specialization  among  them,  difi'erent 
tissues  are  soon  developed. 

Meristem. — The  power  of  cell-di\'ision  and  growth  is  lost  by  most 
tissue  after  a  time,  while  in  other  parts  it  persists  permanently.  Any 
tissue  or  portion  of  tissue  which  possesses  such  power  is  called  Meristem. 
Tissue  may  cease  finally  to  exert  meristematic  power,  or  it  may  resume 
such  power  after  a  time.  All  meristematic  processes  cease  upon  maturity 
of  seed,  recommencing  with  germination. 

Degree  of  Development  Attained  by  the  Embryo  in  the  Seed-condition. — 
The  point  reached  in  the  development  of  any  plant-body  in  the  embry- 
onic condition — that  is,  at  the  maturity  of  the  seed — does  not  depend 
in  any  degree  upon  the  amount  or  kind  of  tissue  or  tissues  developed, 
but  altogether  upon  the  habit  of  the  particular  class  of  plant.  In  some 
embryos,  tissue  differentiation  cannot  be  seen  to  have  taken  place  at 
the  time  of  separation  from  the  parent,  while  in  others  it  has  progressed 
very  far,  though  never  (unless  germination  has  occurred)  to  the  pro- 
duction of  a  true  root.  It  is  impossible,  therefore,  to  fix  upon  any 
particular  developmental  stage  of  stem-structure  as  distinguishing  the 
ungerminated  embryo  from  the  germinated  plantlet.  In  the  following 
sketch  of  its  development,  then,  no  note  is  taken  of  the  resting  period 
in  the  seed-stage,  but  the  process  is  followed  as  though  it  were  con- 
tinuous from  fertilization  through  germination  and  into  the  mature 
condition  of  the  plant. 

Although  of  primary  importance  scientifically,  and  of  great  interest, 
the  phenomena  of  germination  are  not  important  from  the  standpoint 
of  pharmacognosy,  and  a  mere  outline  of  them  is  here  given. 

Vitality  of  Seeds. — Animation  is  probably  not  entirely  suspended 
during  the  resting  period  of  the  seed.     That  is,  there  is  an  apparent 


GERMINA  TION 


137 


iiitorc-luin<,^o  of  substance,  due  to  vital  action,  hetweeu  the  seed  and  the 
surrounding  atmosphere,  altliough  c\treniel\'  shght,  so  long  as  the  former 
possesses  its  vitality. 

The  evidence  as  to  h-ngtii  of  time  (hiring  wliich  seeds  can  retain  their 
vitaHty  is  extremely  contradictory,  and  the  greatest  diversity  of  oj)inion 
exists  concerning  this  point.  Our  best  authorities  bclicxc  that  we  have 
no  conclusive  e\'idciic(>  that  the  period  is  longer  than  about  fifty  years, 
although,  u])on  the  other  hand,  we  have  no  positive  evidence  that  it  is 
not  ver\'  nuich  Jouiicr. 


Germination. —  ('oiidifions  of  (IcnnliKifioii.-  (u-rniination  dciiends 
u])on  (Da  specific  temperature,  varying  for  seeds  of  dillerent  species 
and  for  those  of  the  same  species  when  they  hav(>  become"  habituated 


138  GENERAL  STRUCTURE  OF  ROOT  AND  STEM 

to  essentially  different  climatic  conditions;  (2)  a  specific  saturation,  also 
varying  with  different  seeds — that  is,  the  absorption  of  an  amount  of 
water  bearing  a  fixed  ratio  to  the  weight  of  the  seed :  (3)  a  partially  fixed 
degree  of  light  exclusion;    (4)  the  presence  of  free  oxygen. 

The  Process  of  Germination. — Under  these  conditions,  ready  prepared 
nutriment  is  dissolved,  other  forms  become  digested  by  special  vegetable 
ferments  (Enzymes)  present,  heat  is  developed,  cell-propagation  and 
cell-growth  take  place,  and  the  development  and  growth  of  a  plant  from 
the  embryo  commence.  By  the  growth  of  the  embryo,  the  radicle  is  pro- 
truded through  the  micropyle,  the  rest  of  the  body  soon  following  and 
leaving  the  embryo  free  from  its  coats,  or  the  body  may  remain  enclosed 
in  the  coats  for  some  time.  The»  radicle,  if  it  does  not  already  point 
directly  downward,  turns  in  that  direction  and  develops  into  a  root 
(Figs.  417  and  419).  The  cotyledons  may  then  separate  completely, 
leaving  the  plumule  or  second  phytomer  to  develop  from  the  apex, 
between  them  (Fig.  416),  or  the  cotyledons  may  remain  in  contact,  and 
the  plumule  or  second  phytomer  burst  forth  from  between  the  bases 
of  their  petioles  (Fig.  418).  The  end  of  the  embryo  opposite  to  the 
radicle,  if  it  does  not  already  point  upward,  turns  in  that  direction  and 
develops  as  the  apex  of  the  stem. 

The  Epicotyl  and  Hypocotyl. — The  stem  above  the  cotyledons  is  called 
the  Epicotyl,  that  below  them  the  Hypocotyl. 

Cellular  Development  and  Growth. — The  cellular  nature  of  develop- 
ment and  growth  demands  a  general  knowledge  of  histology  for  their 
understanding,  so  that  we  shall  here  consider,  so  far  as  possible,  only 
the  gross  results  of  the  processes,  or  such  characters  of  the  root  and 
stem  as  can  be  demonstrated  by  other  than  histological  methods.  Such 
references  to  cellular  structure  as  are  here  necessary  are  given  rather 
figuratively  than  technically.  The  mode  of  growth  in  root  and  stem, 
and  the  structures  resulting,  are  sufficienti}'  different  to  require  separate 
treatment.  Although  the  forms  of  structure  liere  considered  as  applying 
to  the  root  concern  only  flowering  plants  and  the  very  highest  of  the 
cryptograms,  yet  the  description  is  applicable  to  all  roots  used  in 
medicine. 

Structure  of  the  Root. — Upon  examining  a  transverse  section  of  the 
root  in  its  rudimentary  condition,  it  is  possible  to  distinguish  three 
bodies  of  tissue  exhibiting  characteristic  differences  in  their  cellular 
elements  (P'ig.  420). 

The  Plerom,  Pleriblem,  and  Dermatogen. — The  central  portion  is 
occupied  by  a  solid  cylinder  called  the  Plerom  (a).     Outside  of  this 


STRUCTURES  DEVELOPED  FROM   THE  PERIBLEM 


139 


there  is  a  hollow  cylinder  called  the  Periblem  (6),  and  still  outside  of 
this  and  upon  the  surface  of  the  root  a  second  hollow  cylinder,  the 
Dermatogen  (c). 

Structures  Developed  from  the  Dermatogen. — The  last  mentioned 
develops  a  primary  covorhig  called  the  Ki)i(k'rmis  (Fig.  422,  a). 

The  Root-cap. — The  ci)idermis  consists  in  its  earliest  stage,  and  there- 
fore at  the  very  tip,  of  a  number  of  layers  of  cells  which  protect  the 
apical  growing  point  of  the  root,  and  is  therefore  called  at  that  point 
the  Root-cap  (Fig.  41 G,  a-b).  Toward  the  summit  of  the  root-cap  the 
outer  layers  of  cells  successively  wear  off  or  are  cast  off,  so  that 
the  epidermis  becomes  reduced  to  a  single  thickness  of  cells. 


Fig.  420.  Diagram  illustrating  arrangement  of  ground-tissues  of  root:  a,  plerom;  b,  periblem:  c, 
dermatogen.  421.  Plerom  enclosed  by  endodermis  (c),  with  first  appearance  of  bundles:  e,  xylem- 
bundle;  /,  phloem-bundle;  g,  medullary-raj- :  h,  pericycle;  i,  temporary  pith.  422.  The  same  in 
a  more  advanced  stage,  the  outer  portions  also  present:  a,  epiderm;  b,  liypoderm;  c,  endodcrm  (cortex 
between  b  and  c);  e,  xylcm-bundles  now  meeting  at  center;  /,  phloem-bundle;  (?,  medullary-ray;  h, 
pericycle;  i,  cambium  of  the  primary  phloem-bundle;  y,  of  the  primary  xylem-bundle;  2,  of  the 
primary  medullary-ray. 


The  Ruot-hdirs  and  Pclij'croiis  Layer.- — Here  it  frequently  (lc\clops  a 
dense  covering  of  Root-hairs  which  adhere  tenaciously  to  the  soil  and 
perform  various  processes  connected  with  absorptit)n  (Fig.  410,  h-c). 
For  this  reason,  this  portion  of  the  epidermis  of  the  root  is  known 
as  the  Piliferous  Layer. 

The  Epidermis  Proper. — Still  farther  uj)  these  hairs  have  fallen 
away,  and  the  single  layer,  after  slight  modifications,  becomes  converted 
into  the  epidermis  i)roper.  This  has  a  variable  duration  in  difl'erent 
plants  and  is  consequently  found  covering  the  root  for  a  greater  or  less 
distance  upward.  Almost  always  its  duration  is  very  short.  It  either 
disappears  altogether,  being  replaced  by  a  structure  (Periderm)  devel- 
()])c<l  from  the  periblem,  or  in  rare  cases  itself  develops  into  the  periderm. 

Structures  Developed  from  the  Periblem. — The  periblem  of  the  root 
develops  into  the  Cortex  (Fig.  422  between  b  and  r),  consisting  of  a 
number,  often  a  large  number,  of  layers  of  cells. 


140       GENERAL  STRUCTURE  OF  ROOT  AND  STEM 

The  Ilypodermis. — Its  outermost  portion,  usually  of  one  layer  of 
cells,  presents  a  different  appearance  from  the  subjacent  layers,  and 
is  the  Hypodermis  (Fig.  422,  h)  in  the  case  of  the  root  becoming  the 
Exodermis.  The  hypoderm  lies  against  the  inner  face  of  the  epiderm 
(a),  while  that  persists,  l)ecoming  afterward  the  superficial  layer,  and 
persists  for  a  longer  or  shorter  period.  Its  characteristics  are  of  great 
importance  in  histological  determinations. 

The  Endodermis. — The  innermost  layer  of  the  primary  cortex  is  even 
more  distinct  in  appearance  than  the  hypoderm,  and  is  the  Endodermis 
(c).  It  lies  in  contact  with  the  outer  surface  of  the  structure  developed 
from  the  plerom. 

Disappearance  of  the  Primary  Cortex. — The  production  of  primary 
cortex  is  quickly  completed.  If  then  the  growth  inside  of  it  continues 
indefinitely  it,  in  most  plants,  involves  the  destruction  and  disappearance 
of  the  primary  cortex,  which  must  be  replaced  by  some  other  covering. 

Promsion  by  Phellogen  for  a  New  'Covering. — A  new  meristematic 
region  must  then  be  established  for  the  purpose  of  manufacturing  such 
a  covering.  This  almost  always  arises  in  some  part,  and  it  may  be  in  any 
part,  of  the  primary  cortex.  It  is  the  Phellogen  (Fig.  422,  d).  The 
phellogen  may  be  in  the  form  of  a  continuous  circle  or  the  usual  form 
in  that  of  blades  or  plates  (d),  variously  placed  and  directed. 

Periderm  and  PheUoderm. — Upon  its  outer  surface  the  phellogen 
develops  corky  tissue,  the  Periderm,  and  upon  its  inner  a  secondary 
cortex,  the  PheUoderm.  Occasionally  it  will  produce  only  periderm  or 
only  phelloderm. 

Secondary  Periderm. — As  the  periderm  becomes  impervious  to  the 
nourishing  fluids,  it  and  all  the  tissues  exterior  to  it  must  die,  and  may 
be  cast  off,  a  new  phellogen  then  appearing  farther  toward  the  interior 
to  form  a  new  periderm,  so  that  we  may  have  successive  periderms — 
the  primary,  secondary,  and  so  on.  This  process  is  comparatively'  rare 
in  the  case  of  the  root,  very  common  in  that  of  the  stem. 

The  Bork. — In  such  cases,  the  corky  layers  which  become  successively 
superficial,  observed  in  the  scales  of  bark  which  peel  off  from  tree-trunks, 
constitute  the  Bork  or  Rhytidoma.  Bork  is  called  Ring-bork  when  it 
forms  a  cylinder,  Scale-bork  when  it  occurs  in  detached  plates.  It  must 
be  noted  that  the  origin  of  the  bork,  and,  as  will  be  shown  later,  its 
structural  nature  dependent  thereon,  will  depend  upon  the  depth  at 
which  the  phellogen  develops.  The  same  feature  will  also  determine  the 
amount  and  character  of  the  tissue,  if  any,  existing  between  it  and  the 
structure  developed  from  the  plerom. 


STRUCTURES   DEVELOPED  FROM    THE  rJ.EROM  141 

No  Fibro-mscular  TLs-suc  Developed  j'roin  Perihieiii.—  Su  tissue 
developed  directly  or  indirectly  from  the  j)eril)lein  is  in  the  form  of 
distinct  and  rej^ular  bundles  of  vessels,  though  irregular  and  isolated 
or  anastomosinti  tubes  are  frequently  develojjed  by  it. 

Structures  Developed  from  the  Plerom.  The  S1ele.~  The  essential 
characteristic  of  the  body  developed  from  the  plerom  of  the  root  is 
that  it  is  invested  by  the  endodermis  and  is  free  from  any  other  endo- 
dermal  development  in  any  part.  It,  therefore,  constitutes  a  Stele 
(all  inside  of  c),  which  in  the  root  is  always  in  the  form  of  a  Central 
Cylinder. 

Differentiation  in  the  Cells  of  the  »S7t7f'.— The  plerom  exhibits  at  first 
only  sHght  differences  in  the  appearance  of  its  cells  (Fig.  420,  a),  and 
a  transverse  section  of  it  viewed  with  the  microscope  might  be  figura- 
tively compared  to  looking  down  upon  a  honeycomb  built  in  a  cylin- 
drical tin  box,  the  latter  representing  the  endodermis,  and  in  longitudinal 
section  to  a  longitudinal  section  through  the  same.  This  constitutes 
the  Ground-tissue  of  the  Stele.  Farther  away  from  the  tip,  however, 
it  would  be  found  that  groups  of  its  cells  (Fig.  421,  e  and/)  had  elon- 
gated in  a  longitudinal  direction,  and  these,  to  continue  our  illustration, 
might  be  compared  to  bundles  of  pencils  or  quills  set  in  the  honeycomb. 
Mingled  among  the  elongated  cells  of  the  bundle,  however,  are  many 
which  have  not  elongated. 

Medullary  Rai/.'i. — These  bundles  would  be  arranged  in  a  circle 
separated  from  one  another  })y  more  or  less  of  the  honeycomb  tissue, 
these  sej)arating  ])ortions  corres])()nding  to  the  Medullary  Jvays  of  the 
Stele  (g). 

The  Pcriri/cle. — From  the  endodermis  they  would  be  separated  by 
one  or  more  continuous  circles  of  the  honeycomb  cells,  corresponding 
to  the  Pericyde  or  "  Pericambium"  (h).  For  a  time  there  would  also 
be  left  a  central  jiortion  (/),  consisting  of  unchanged  cells,  forming  a 
temporary  Medulla  or  pith. 

The  Vessels. — The  elongated  cells,  which  constitute  the  imj^ortant 
elements  of  the  bundles,  are  joined  end  to  end  with  other  similar  ones 
still  farther  uj)  in  the  older  jKirt  of  the  structure.  At  first  the  enii  walls 
of  these  abutting  cells  sei)arate  their  cavities  from  one  another,  but 
later  these  disappear  in  those  of  some  bundles,  becoming  jjcrforatcd  in 
those  of  others,  so  that  the  cavities  become  more  oi-  less  contiinious, 
forming  the  Vessels,  extending  throughout  the  root  and  intoaiul  through 
the  stem  above.  The  bundles  thus  formed  are  thus  of  two  kinds,  aher- 
nating  in  the  circle. 


142  GENERAL  STRUCTURE  OF  ROOT  AND  STEM 

The  Xylem-  or  Wood-bundles. — Each  of  those  of  one  kind  (Fig,  422,  e) 
extends  gradually  toward  the  center  by  the  successive  development 
there  of  vessels  or  cells  associated  with  the  vessels  of  the  bundles.  Upon 
meeting  there,  the  bundles,  of  course,  cut  off  the  previously  existing 
central  communication  between  the  medullary  rays,  which  are  now  left 
as  isolated  plates  or  wedges  between  the  bundles,  the  temporary  pith 
being  thus  obliterated.  These  bundles,  which  meet  at  the  center,  are 
known  as  the  Xylem-bundles  or  Wood-bundles,  and  constitute  the 
wood}'  portion  of  the  root. 

The  Ducts. — The  tubes  formed  as  described  above  are  the  Ducts. 
In  a  few  plants  which  we  have  to  consider,  the  Gymnosperms,  no 
series  of  cells  lose  their  end-walls  as  above  described  so  as  to  become 
converted  into  continuous  tubes  or  ducts,  though  they  connect  by 
perforations. 

The  Phloem-  or  Sieve-bundles  and  Sieve-tubes. — The  other  bundles 
(Fig.  422,  /)  which  have  been  described  as  alternating  with  the  xylem-, 
or  wood-bundles,  possess  as  their  important  element  those  cells  which 
become  connected  by  perforations  in  the  form  of  sieves,  and  are  known 
as  the  Phloem-bundles. 

Collectively  they  form  what  is  known  as  the  Sieve-tissue,  or  Cribrose- 
tissue,  of  the  plant,  and  their  intercommunicating  tubes  are  the  Sieve- 
tubes.  This  tissue  characterizes  the  Gymnosperms  as  well  as  the 
Angiosperms.  The  phloem-bundles  do  not  extend  toward  the  center,  as 
do  the  xylem-bundles,  but  stand  isolated,  each  between  two  medullary 
rays,  which  respectively  separate  it  from  the  xylem-bundle  upon  either 
side. 

The  Fibers. — In  connection  with  the  ducts,  or  their  equivalents 
in  the  gymnosperms,  and  the  other  tissues  of  the  xylem-bundles,  strong 
fibers  develop,  the  Wood-fibers,  while  in  connection  with  the  sieve-tubes 
and  other  tissue  of  the  phfoem-bundles  very  similar  fibers,  the  Bast- 
fibers,  usually  develop.  The  phloem-bundles,  therefore,  ordinarily 
become  Bast-bundles. 

Fibro-vascular  Bundles. — Vascular  bundles  in  which  fibers  develop 
are  known  as  Fibro-vascular  bundles. 

Secondary  Groivth  of  the  Stele. — The  condition  now  reached  by  the 
root  constitutes  the  completed  primary  structure  of  its  stele.  The 
student  should  not  fail  to  note  that  the  primary  structure  refers  only 
to  the  very  smallest  roots,  and  that  he  need  not  expect  to  encounter  it 
in  any  roots  in  a  condition  to  be  used  medicinally.  His  examination 
of  roots  in  Pharmacognosy  will,  therefore,  relate  to  the  secondary 


CONTINUOUS  MULTIPLICATION  OF  THE  STRUCTURES      143 

structure,  an  account  of  wliich  will  follow.  With  the  production  of  the 
primary  structure,  growth  and  increase  in  thickness  may  cease  (most 
]\Ionoc()tyledons),  in  which  case  the  periderm  changes  which  we  have 
recorded  will  not  occur.  On  the  other  hand,  secondary  growth  may 
take  place,  in  which  case  those  changes  are  more  or  less  completely 
induced. 

Development  of  the  Cambium. — In  such  case,  the  cells  touching  the 
phloem-bundles  upon  their  inner  faces  and  n])on  their  sides  become 
meristematic  and  proceed  to  produce  xylem-tissue  upon  their  inner 
faces  and  secondary  phloem  upon  their  outer,  in  contact  with  the 
primary  tissue  of  that  kind.  Each  such  arc  of  meristem  (Fig.  422,  x) 
becomes  the  Cambium  of  that  bundle. 

Completion  of  the  Bundles. — At  the  same  time  the  cells  lying  in  contact 
with  the  outer  surfaces  and  with  the  sides  of  each  xylem-bundle  similarly 
become  a  cambium  for  that  bundle  {y),  and  sometimes  produce  second- 
ary xylem,  upon  their  inner  faces,  in  contact  with  the  primary  xylem 
there,  and  secondary  phloem.upon  their  outer  faces.  By  these  processes 
each  bundle  which  undergoes  them,  previously  consisting  of  one  kind 
of  tissue,  therefore  an  incomplete  bundle,  comes  to  consist  of  both  kinds 
of  tissue  and  becomes  a  complete  bundle. 

The  Cambium-circle. — Connecting  the  cambium  arcs  of  the  adjacent 
bundles,  a  cambium  arc  (2)  forms  in  the  intervening  medullary  ray,  and 
this  produces  secondary  medullary  ray  tissue  on  both  its  inner  and  its 
outer  face.  There  is  thus  formed  a  continuous  cylinder  of  cambium 
(.r,  y,  z),  though  a  somewhat  irregular  and  wavy  cylinder,  standing 
between  the  zone  formed  within  by  the  primary  and  secondary  xylem- 
bundles  and  their  intervening  portions  of  the  medullary  rays,  and  the 
outer  primary  and  secondary  phloem-bundles  (when  the  latter  develop) 
with  their  intervening  portions  of  the  medullary  rays.  Although  this 
cambium  forms  a  cylinder,  as  stated,  it  is  usually  referred  to  as  the 
"  Cambium-ring,"  or  "  Cambium-circle,"  because  it  presents  this  appear- 
ance  in  transverse  section. 

Continuous  Multiplication  of  the  Structures. — Provision  is  now  nuule 
for  the  growth  of  all  portions  of  the  stele.  Additional  complete  fibro- 
vascular  bundles  are  now  developed  in  the  medullary  ray  spaces  between 
the  others,  fed  by  a  portion  of  cam])ium  in  a  similar  manner.  New 
medullary  rays  also  develop  in  the  substance  of  the  bundles.  We  thus 
have  developed  upon  the  inside  of  the  cambium-cylinder  a  cylinder  of 
xylem,  solid  except  for  the  blades  of  medullary  ray  tissue  ])enetrating 
it  nearlv  to  the  center,  and  outside  of  the  cambium-cvlinder  a  hollow 


144  GENERAL  STRUCTURE  OF  ROOT  AND  STEM 

cylinder  of  phloem  tissue  or  bast  tissue,  continuous  except  for  similar, 
but  of  course  much  shorter,  medullary  rays. 

It  has  been  said  above  that  the  portions  of  the  cambium-circle 
opposite  to  the  primary  wood-bundles  "may"  produce  secondary 
wood  upon  their  inner  faces  and  secondary  phloem  upon  their  outer. 
While  this  does  take  place  in  some  roots,  it  usually  does  not,  only 
pericycle  tissue  forming  at  those  points  on  both  the  inner  and  outer 
faces  of  the  cambium. 

The  above  constitutes  the  secondary  structure  of  the  root-stele,  and 
any  further  growth  which  may  occur,  except  for  the  development  of 
branches,  considered  hereafter,  is  merely  a  continuation  of  the  process 
described  as  secondary  growth. 

The  Annual  Rings. — When  an  annua!  resting-period  in  growth  occurs, 
the  ducts  of  the  xylem  produced  toward  the  close  of  the  year's  growth 
will  be  conspicuously  smaller  than  those  produced  at  the  beginning,  so 
that  conspicuous  Annual  rings  are  produced  in  many  woods. 

The  Duramen  and  Alburnum. — ^After  a  tree  has  attained  a  certain  age, 
the  wood  at  the  center  dies,  and  becomes  dryer  and  harder  and  of  a 
different  color  from  the  living  wood  outside  of  it,  and  this  dead  portion 
becomes  thicker  year  by  year.  It  is  called  the  Duramen,  or  "Heart- 
wood,"  and  it  often  contains  medicinal  or  coloring  matters.  The  outer 
is  called  the  Alburnum,  or  "Sap-wood."  It  is  the  duramen  only  which 
yields  the  most  of  our  colored  cabinet  lumbers. 

Effects  of  Secondary  Growth  upon  the  Superficial  Structure. — The 
effect  of  secondary  growth  upon  the  structures  external  to  the  bast- 
cylinder  is  extremely  variable,  according  to  the  extent  of  such  growth 
and  the  relations  of  the  phellogen  and  its  structure  and  the  individual 
habit  of  the  plant.  It  has  been  stated  that  the  phellogen  may  develop 
in  any  part  of  the  cortex.  It  may  now  be  stated  that  it  may,  and,  in 
fact,  usually  does,  in  the  root  develop  in  the  bast-cylinder  itself,  so 
that  all  the  parts  external  to  it,  and  even  portions  of  itself,  will  belong 
to  the  periderm,  or  in  the  rare  case  of  Bork-casting  by  the  root,  will 
be  cast  off. 

Origin  of  the  Branches  of  the  Root. — In  all  the  classes  which  yield  our 
medicinal  roots,  the  branches  start  from  the  pericycle  outside  of  a 
xylem-bundle  at  the  point  h  (Fig.  421),  as  it  is  first  developing,  and  grows 
through  the  surrounding  tissue  to  and  from  the  surface.  If  cross- 
sections  have  been  cut  through  a  root  so  as  to  pass  through  its  branches 
also,  the  branches  on  the  older  part  will  appear  as  mature  secondary 
roots.    Those  lower  down  will  be  successively  less  developed,  appearing 


STRUCTURE  OF  STEM  AS  COXTRASTE /)  WITH  Til  A  T  OF  ROOT    145 

at  ItMifftli  uj)()n  the  younger  })()rti()n  as  not  yet  having  made  tlieir  way 
througli  the  overlying  tissues  to  the  surface.  As  the  root  first  formed 
is  called  the  Primary,  so  its  l)ranches  are  called  Secondary.  'J'heir 
structural  develoi)ment  is  a  rejx'tition  of  that  of  the  ])rimary. 

Continuity  of  Root-growth.-  The  continuity  of  growth  in  the  root  is 
uniform — that  is,  there  is  no  di\ision  of  it  into  joiuts  or  ])hytomers. 
There  are  hence  no  regular  distances  at  which  it  hranclus,  and  when 
buds  are  produced  ui)on  it,  as  they  are  in  rare  cases,  their  points  of 
origin  are  not  so  regulated. 

Structure  of  the  Stem  as  Contrasted  with  that  of  the  Root. — (The  follow- 
ing account  of  stem-structure  refers  only  to  the  ordinary  i)lants  of  the 
flowering  class.  At  its  close  a  brief  reference  will  be  made  to  such  others 
as  require  attention  for  the  pur])()ses  of  ])harmacognosy.) 

The  history  of  stem-devel()j)ment  is  best  presented  by  contrasting  it 
with  that  of  the  root,  which  has  already  been  given.  The  three  elemen- 
tary tissues,  dermatogen,  periblem,  and  plerom,  are  also  found  in  the 
young  stem-structure.  The  epidermis  and  other  tissues  of  the  stem  are 
more  variable  than  the  corresj)onding  tissues  of  the  root,  and  the  details 
l)ertain  for  the  most  i)art  to  histology  and  to  the  special  treatment  of 
species  or  groups. 

The  Epidermis. — The  most  im])ortant  distinction  between  the  ej)i- 
dermis  of  root  and  stem  may  be  mentioned  as  the  i)resence  in  the  latter 
of  stomata,  to  be  studied  in  connection  with  the  leaf.  There  is  no 
extra  development  from  the  dermatogen  at  the  tij)  corresi)onding  to 
the  root-cap,  nor  of  hairs  similarly  aggregated  to  those  of  the  root, 
although  hairs  of  many  forms  abound  upon  the  epidermis  of  the  stem. 
Stem-epidermis  may  consist  of  one  or  of  several  layers,  and  if  the  latter, 
they  may  l)e  dissimilar  in  varying  degrees.  Rarely  it  is  i)ersistent, 
being  usually  thrown  off  through  the  growth  of  the  parts  within  it, 
as  has  already  been  considered  in  the  case  of  the  root. 

The  Cortex. — The  i)eril)lem  of  the  stem  develops  structures  in  general 
similar  to  thos(>  of  the  root-pcM-ibU^n,  the  most  imj^ortant  distinction 
being  the  ])r()(lucti(in  of  a  (■hloro])hyll-hiyer.  A  ])riniai"y  cortex,  usually 
somewhat  thinner  than  that  of  the  root  of  the  same  i)lant,  is  bounded 
externally  by  a  hypoderm  and  internally  by  an  endoderm,  and  may 
de\-elo])  tubes  similar  to  tlio-e  mentioned  as  fre(iiientl\-  ])ei-taining  to 
the  root-cortex,  but,  as  in  that  case,  no  true  \a>cular  bundles.  The 
effects  of  growth  within  the  ])rimary  cortex  of  the  root,  leading  to  the 
formation  and  casting  off  of  bork,  we  h;t\e  seen  to  be  of  rare  occurrence. 
In  the  case  of  the  stem,  howc\er,  it  is  of  \  cry  general  occurrence,  so 
10 


146  GENERAL  STRUCTURE  OF  ROOT  AND  STEM 

that  the  entire  account  which  has  been  given  of  the  development  and 
disposition  of  periderm  and  phelloderm  may  be  appKed  with  special 
force  in  the  case  of  the  stem. 

The  Central  Cylinder. — The  principal  differences  between  root- 
structure  and  stem-structure  are  found  in  the  de^'elopments  from  the 
plerom.  Although,  with  the  single  exception,  among  important  medi- 
cinal stems,  of  the  male  fern,  there  is  but  a  single  stele,  in  the  form 
of  a  central  cylinder,  yet  the  development  of  its  structure  is  markedly 
different  from  that  of  the  root.  Leaving  out  of  consideration  exceptions 
which  are  unimportant  in  pharmacognosy,  we  find  that  two  distinct 
types,  of  structure  characterize  respectively  the  monocotyledons  and  the 
dicotyledons  and  gymnosperms.  The  form  characterizing  the  latter 
two  will  be  first  considered. 

TJie  Primary  Bundles. — Vascular  bundles  originate  in  the  plerom  in 
the  form  of  a  circle,  just  as  in  the  case  of  the  root,  the  important  differ- 
ence being  that  each  bundle  consists,  even  in  its  primary  state,  of  both 
phloem  and  xylem,  with  a  cambium  between. 

The  Open  Collateral  Bundle. — The  typical  form  is  that  which  in  the 
root  constitutes  the  secondary  structure — namely,  a  bundle  consisting 
of  xylem  within  and  phloem  without  the  cambium  arc,  and  this  con- 
stitutes what  is  known  as  the  Open  Collateral  Bundle. 

Secondary  Growth. — Secondary  growth  here  consists  in  the  addition 
by  the  cambium  to  each  kind  of  tissue,  and,  in  almost  all  cases,  the 
development  of  new  intermediate  bundles  and  new  medullar}^  rays, 
as  has  been  described  in  the  case  of  the  root.  The  result  is  that  the 
general  plan  of  structure  attained  is  identical  with  that  already  recorded 
as  ultimately  attained  by  the  most  highly  developed  woody  roots. 
There  are,  however,  several  differences  which  must  be  noticed. 

The  Medulla  or  Pith. — The  most  important  is  that  the  primary 
xylem-bundles  do  not  progress  toward  and  meet  one  another  at  the 
center,  so  that  there  is  always  left  there  a  cylinder  of  the  fundamental 
tissue,  constituting  the  ^Medulla  or  Pith,  which  is  connected  through 
the  primary  medullary  rays  with  the  pericycle,  or,  after  the  disappear- 
ance of  that  and  of  the  endodermis,  with  the  cortex. 

The  whole  structure  in  transverse  section  may  now  be  roughly  com- 
pared with  the  wheel  of  a  wagon.  The  pith  corresponds  to  the  hub, 
the  primary  medullary  rays  to  the  spokes,  the  spaces  between  the 
spokes  to  the  primary  wood  wedges,  the  felloe  to  the  bast  product, 
except  that  the  spokes  should  be  seen  extending  through  it,  and  the 
tire  to  the  periderm  in  its  various  forms  of  development. 


DIRECTIONS  OF  SECTION I-SG  FOR  EXAMINATION  147 

Variations  in  Structure.— Altliouj,^!)  the  details  of  tissue-arrangement 
pertain  to  histology,  yet  the  deviations  from  the  above  relative  positions 
of  the  phloem  and  xylem  are  of  such  very  great  importance  in  pharmac- 
ognosy that  they  are  here  referred  to.  We  may  have  (1)  the  Bieollateral 
Bundle,  in  which  a  second  fascicle  of  phloem  is  placed  upon  the  inner 
face  of  the  xylem;  (2)  the  peculiarities  characterizing  the  monoco- 
tyledons, which  will  be  described  later. 

There  are  three  ways  in  which  the  strncture  of  the  root  or  stem  may 
be  examined. 

Directions  of  Sectioning  for  Examination. — 1.  A  Radial  section  is  a 
longitudinal  section  in  a  plane  passing  through  the  center. 

2.  A  Tangential  section  is  a  longitudinal  section  in  a  ])lanc  which 
does  not  pass  through  the  center. 

\\.  A  Transverse  section  is  one  i)assing  exactly  at  right  angles  to 
the  former  two. 

Appearance  of  the  Radial  Section. — The  appearance  presented  by  a 
radial  section  through  a  perfectly  developed  woody  stem  possessing 
open  collateral  btmdles  may  now  be  described  as  follows,  enumerating 
the  structures  upon  either  side  from  the  center  outward:  (1)  Pith; 
(2)  wood  wedges,  with  medullary  rays,  the  latter,  if  primarj^,  communi- 
cating with  the  pith  at  the  center  and  outward  with  the  cortex;  if 
secondary,  extending  outward  like  the  primary,  but  no  farther  inward 
than  the  limit  of  the  ring  in  which  it  originates;  (3)  the  cambium; 
(4)  the  bast  bundles,  separated  by  their  medullary  rays;  (5)  the  phello- 
derm,  phellogen,  and  periderm,  the  relations  of  which  to  one  another 
and  to  the  bast,  and  the  structure  of  which,  cannot  be  specified,  owing 
to  the  extreme  variation  which  they  dis])lay  in  different  stems.  The 
composition  of  the  bork,  if  any,  will  also  depend  upon  the  point  of 
development  of  the  phellogen  and  its  form  upon  the  form  of  the  latter. 

Appearance  of  the  Transterse  Section. — Upon  a  transverse  section, 
the  same  structures  as  above  recorded  will  appear,  but  instead  of  being 
in  the  form  of  thin  strips  upon  either  side  of  the  center,  they  will  be  in 
the  form  of  concentric  rings  around  it.  Thus  the  center  is  seen  occupied 
by  a  circle  of  pith,  outside  of  which  is  a  zone  of  xylem  or  wood  tissue, 
separated  by  longer  or  shorter  medullary  ra\s  into  its  primary  and 
younger  wood  bundles.  Outside  of  the  first  ainnial  ring  is  where  the 
intermediate  or  secondary  bundles  make  their  first  appearance.  The 
secondary  medullary  rays  (Fig.  42)^,  a)  will  be  found  not  to  extend 
inward  beyond  the  production  of  tissue  of  that  year.  Instead  of  appear- 
ing as  blades,  as  they  did  in  the  radial  section  (Fig.  42;>,  b),  the  medullary 


148 


GENERAL  STRUCTURE  OF  ROOT  AND  STEM 


rays  now  appear  as  narrow  lines.  That  is,  we  now  see  the  edges  of  the 
blades  whose  sides  were  before  seen.  Passing  outward  beyond  the 
last  of  the  annual  rings,  which  successively  exhibit  a  greater  number  of 
wood-bundles  and  medullary  rays,  we  reach  the  cambium-ring.  Outside 
of  this  we  find  the  phloem  or  bast  bundles  sejjarated  by  medullary  rays 
continuous  with  those  of  the  wood  cylinder,  and  still  outside  of  this  the 
periderm. 


Fig.  423.  Diagram  illustrating  section  of  woody  portion  of  dicotyledonous  stem:  a,  edges  of  medul- 
lary rays  as  seen  in  transverse  section;  6,  sides  of  same  as  seen  in  radial  section;  c,  ends  as  they  would 
appear  in  tangential  section. 


Appearance  of  the  Tangential  Section. — The  appearance  of  a  tangen- 
tial section  will  depend,  of  course,  upon  the  tissues  through  which  it 
passes.  If  it  cuts  the  medullary  rays  these  will  appear  neither  as  the 
broad  sides,  as  at  h,  nor  the  edges  of  blades,  as  at  a,  but  as  transverse 
sections  of  them,  as  at  c.  If  the  ray  consists  of  but  one  row  of  cells  in 
width,  then  such  a  row  will  be  exhibited  upon  the  tangential  section,  its 
vertical  height  varying  from  a  very  few  to  quite  a  large  number  of  cells. 
If,  upon  the  other  hand,  it  possess  a  lateral  breadth  of  several  thick- 
nesses of  cells,  of  5  in  our  figure,  this  condition  will  exist  only  at  its 
middle  portion.  At  its  upper  and  lower  limits  it  will  ordinarily  be 
reduced  to  the  thickness  of  a  single  cell,  so  that  the  tangential  aspect 
of  a  medullary  ray  is  almost  always  that  of  an  ellipse,  broad  or  narrow, 
according  to  the  numl)er  of  rows  of  cells  of  which  it  consists,  in  contrast 
with  the  extent  of  its  upward  and  downward  extension. 


STRUCTURE  OF    THE   MOXOCOTYLEDOXOUS  STEM  119 

Til  sonic  stems  the  ])illi  oi'  incdull.-i  (lis;ii)|)c;irs  more  or  less  eom- 
])Ietely  after  a  time,  lea\in<j;  a  eyliiidrieal  liollow  cavity.  This  may  he 
eoiitiiiiious  throii,y;h  the  nodes  or  sejjarated  at  those  i)oiiits  hy  transverse 
partitions. 

Structure  of  the  Monocotyledonous  Stem.  In  monoeolyledons  (Fij;. 
4lM)  \\(>  ha\-e  the  Closed  hnndle,  in  which  the  one  element  surrounds 
and  encloses  the  other.  In  all  medicinal  monocotyledonous  stems 
possessing  such  hundles,  it  is  the  xylem  which  encloses  the  phloem.  If 
the  two  cylinders  thus  formed  have  a  common  center,  which  form  is 
not  very  common,  it  is  called  a  Concentric  hnndle.  It  is  clear  that  in 
the  last  two  forms  a  caml)inm  cylinder,  such  as  distinguishes  the  stele, 
possessing  the  form  i)revi()usly  considered,  cannot  be  formed.    In  such 


Fig.  424.    Transverse  section  of  monocotyledonous  stem:  a,  closed  hundles  scattered  through  paren- 
chyma;   6,  nucleus  sheath,  or  cndodermis. 

plants  indefinite  growth  in  thickness  of  the  hundles  ohviously  cannot 
occur,  and  the  same  is  true  of  the  entire  stele,  unless  new  hundles  shall 
develo])  in  it.  Usually  this  does  not  occur,  hut  if  the  ui)i)er  portion  of 
the  plant  shall  l)ranch  and  continue  to  extend  its  leafy  surface,  meristem 
tissue  will  then  form  toward  the  outer  i)ortion  of  the  stele,  and  from 
this  new  hundles  will  successively  arise,  so  that  the  thickness  of  the 
trunk  will  kee])  ])aee  with  the  extension  of  the  crown,  notwithstanding 
that  the  individual  hundles  do  not  increase  in  thickness  after  the  com- 
pletion of  their  primary  structure.  In  stems  i)ossessing  this  form  of 
hundles  the  latter  (Fig.  424,  a)  are  found  more  or  less  scattered  through 
the  fundamental  or  medullary  tissue,  though  there  is  commonly  more 
or  less  of  a  concentration  of  them  in  some  one  region,  usually  toward 
the  i)eriphery  of  the  stele. 


150       GENERAL  STRUCTURE  OF  ROOT  AND  STEM 

The  Nucleus-.^ heath. — The  eiulodcnnis  of  such  })hints  is  commonly 
known  as  a  Xucleus-sheath  (6). 

Polystelar  Stems. — Finally,  we  note  that  in  many  plants,  represented 
among  drugs  by  the  ferns,  the  stem  possesses  a  number,  usually  definite 
for  the  species,  of  vascular  bundles,  or  groups  of  them,  each  invested  by 
its  own  endodermis,  each  being  thus  a  stele.  Such  stems  are,  therefore, 
called  Polystelar.  In  such  plants  no  epidermis  is  developed,  the 
hypoderm,  developed  from  the  periblem,  being  superficial. 

The  Bark. — Its  Nature. — The  Bark  is  everything  external  to  the 
cambium.  It  has  been  proposed  to  remove  the  word  "bark"  from 
common  language,  or  to  ignore  its  fixed  common  meaning,  and  to 
convert  it  into  a  technical  name  for  the  bork.  Experience  with  English- 
speaking  people  leaves  no  hope  that  thej^  will  consent  to  give  up  a  word 
employed  so  widelj'  and  in  such  important  ways,  and  its  technical  use 
can  apparently  result  only  in  the  introduction  of  a  confusion,  which  is 
more  wisely  avoided  by  the  coining  of  some  new'  name,  if  that  of  bork 
is  seriously  objectionable,  which  does  not  appear  to  be  the  case. 

Importance  of  the  Bark  in  Pharmacognosy. — Viewed  from  the  stand- 
point of  pharmacognosy,  the  bark,  especially  when  detached  from  the 
remainder  of  the  root  or  stem,  is  one  of  the  most  important  portions 
of  the  plant.  As  has  been  seen,  it  is  not  a  simple  structure,  but  develops 
in  part  from  the  plerom,  as  well  as  from  the  periblem,  and  bears  fre- 
quently, although  this  is  not  true  of  any  detached  medicinal  bark,  the 
epidermis  as  well. 

Layers  of  the  Bark. — In  practice,  the  bark  is  commonly  differentiated 
into  three  layers — the  Endophloeum,  that  portion  resulting  from  the 
plerom;  the  Mesophloeum,  which  is  either  the  primary  cortex,  or  the 
products  of  a  phellogen  developing  external  to  the  endophloeum,  or 
both  when  they  exist  together;  and  the  Exophloeum,  consisting  of  a 
primary  periderm.  If,  as  is  not  the  case  in  any  medicinal  bark,  the 
epidermis  persist,  it  will  form  the  exophloeum.  It  has  already  been 
made  clear  that  a  bark  can  come  to  want  successively  its  exophloeum, 
mesophloeum,  and  even  the  outer  part  of  its  endophloeum,  as  is  seen  in 
some  Cinchona  bark,  from  old  trees. 

The  study  of  barks  includes  a  close  examination  of  the  cellular 
elements,  as  a  preparation  for  which  histological  work  is  absolutely 
necessary.  Examination  of  its  gross  characters  involves,  as  the  more 
important  features,  its  extreme  and  average  thickness,  its  manifest 
layers,  as  seen  with  a  lens  on  transverse  or  radial  section,  their  relative 
thickness,  color,  markings,  consistency  as  shown  by  fracture,  their 


THE  BARK 


151 


separability  from  one  another,  that  is,  into 
laminae,  together  with  the  snrfac-e  char- 
acters of  the  latter,  the  external  color  and 
level  markin<;s,  the  jiresence  and  natnre  of 
parasites,  and  the  color  and  inequalities  of 
the  iinicr  surface. 

The  Laminae-  The  laminae  do  not 
dcixMid  entirely  upon  diifcrent  tissue  com- 
position. The  same  tissue,  produced  at 
diiVcrent  times,  may  ])resent  differences 
sufficient  to  result  in  different  degrees  of 
cohesion,  as  well  as  markedly  different 
color,  at  different  depths,  so  that  separation 
may  readily  occur,  or  they  may  readily  l)e 
distinguished  in  sections. 

Section-markings. — Groups  or  radial  or 
tangential  rows  of  tissue-elements,  differing 
from  those  adjoining,  frequently  produce 
gross  markings  on  the  section-surface. 

Fracture. — The  fracture  of  barks  or  of 
their  individual  layers  is  denominated  in 
general  as  being  brittle  or  tough,  ^'ari()us 
modifications  are  soft,  earthy,  granular, 
horny,  waxy,  fibrous,  splintery,  or  flexible. 
A  bark  may  be  flexible  hi  one  direction  and 
not  in  another. 

The  Outer  Surface. — The  outer  surface  is 
described  in  general  as  being  harsh,  rough, 
downy,  smooth  or  shiny,  and  its  luster  may 
be  waxv,  ^•itrcons,  and  so  on.     Some  of  the 


Fig.  425.  Section  of  young  Calisaya  bark,  showing  wrinkling 
in  drying.  42G.  Section  of  old  Succirubra  bark,  showing 
ridging. 


Fig.  127.  (^lili  of  mature  Cali- 
saya bark,  sliowing  transverse  and 
longitudinal  fissures. 


152       GENERAL  STRUCTURE  OF  ROOT  AND  STEM 

elements  causing  roii^-hiiess  may  require  mieros('()])ical  examination 
for  their  demonstration,  while  others  are  otherwise  manifest. 

Ridges  and  Furrows. — Care  must  be  taken  to  distinguish  between 
ridging  and  furrowing  of  different  kinds.  One  kind  is  caused  by  a 
longitudinal  wrinkling  in  drying,  as  in  young  Calisoya  (Fig.  425). 
Another  is  owing  to  transverse  (as  in  old  Calisaya)  or  longitudinal  (in 
the  same)  fissuring  (Fig.  427).  Another  is  caused  by  the  elevation  of 
corky  ridges,  or  rows  of  corky  warts,  which  may  or  may  not  become 
confluent  in  variable  degree  (as  in  Succiruhra,  Fig.  426).  Fissures  may 
characteristically  open  in  the  crest  of  a  ridge  or  in  the  otherwise  un- 
changed siu-face. 

Color-markings. — Most  color-variegations  are  due  to  lichens  or 
other  parasites,  and  those  due  to  lenticels  are  also  very  common.  A 
single  color  or  shade  of  color  of  the  inner  surface  is  rarely  characteristic, 
as  it  changes  very  greatly  with  age  in  keeping;  but  a  carefully  arranged 
series  of  them  may  be  made  diagnostic  in  many  cases. 

The  Inner  Surface. — The  important  characteristics  of  the  inner 
surface  depend  upon  the  projecting  bast-bundles  caused  by  contracting 
medullary  rays.  Very  rarely,  indeed,  is  the  surface  so  free  from  these 
inequalities  that  it  can  be  properly  described  as  smooth.  The  slightest 
manifestation  of  the  bundles  gives  the  Striate  condition.  The  striae 
must  be  examined  as  to  length,  straightness,  direction  as  contrasted 
with  the  axis  of  the  bark,  apparent  interconnection  at  the  end,  width, 
elevation,  and  sharpness,  with  the  complementary  characters  of  the 
intervening  furrows  or  pits.  Some  barks  show  a  tendency  to  separate 
into  laminae  which  run  obliquely  out  upon  the  inner  face,  appearing 
there  as  partially  separated  tongue-shaped  splinters. 

No  attempt  has  ever  yet  been  made  to  classify  the  markings  of  the 
inner  surfaces  of  dried  barks,  and  to  provide  a  terminology  for  them. 
In  the  absence  of  this  important  treatment,  it  is  difficult  to  teach  the 
details  of  the  subject,  except  by  the  use  of  the  actual  objects. 


('  II  A  PTK  K     X  1  \' 

VERTICAL  AND   LATERAL  EXTENSIONS  AND  APPENDAGES 
OF  THE  STEM 

Origin  of  Branches  and  Leaves. — Examining  a  radial  section  of  the 
tip  of  the  stem  (Fig.  4)  we  find,  in  addition  to  the  structures  already 
considered  as  helonging  ])rimarily  to  itself,  protuberances,  consisting 
of  masses  of  meristem  tissue  belonging  to  the  periblem  and  the  derma- 
togen.  Shortly,  each  of  these  tissue-masses  assumes,  in  a  general  way, 
the  condition  of  the  primary  growing  point  of  the  main  stem.  Some 
of  them  will  develop  into  leaves,  the  structure  of  which  will  be  con- 
sidered farther  on,  others  into  branches,  which  latter  j)r()cess  is  a  mere 
repetition  of  that  already  considered  in  relation  to  the  })rimary  stem. 
In  either  case,  the  vascular  bundles  exhibit  a  connection,  variable  in  its 
details,  with  those  of  the  stem  from  which  it  develops. 

Arrangement  of  the  Leaves  and  Branches. — The  normal  method  is  for 
a  l)ranch  and  leaf  to  develop  together,  the  former  in  the  axil  of  the 
latter,  as  already  recorded.  If  two  or  more  leaves,  with  their  branches, 
develop  at  the  same  node,  it  results  in  the  opposite  or  verticillate 
arrangement.  If  but  one,  then,  of  those  developing  at  different  levels, 
each  is  successi\ely  separated  from  the  former  by  a  uniform  portion  of 
the  stem  circumference,  so  that  a  spiral  arrangement  results.  This 
s])iral  will  be  considered  when  we  come  to  the  study  of  the  leaf. 

Growth  of  the  Internodes.  The  ])oiiit  at  which  one  or  more  leaves 
de\elop  has  alread\'  been  defined  as  the  node,  and  the  poi'tion  of  stem 
intervening  between  two  nodes  as  the  internode.  At  first  tlu-  internodes 
are  so  short  as  to  be  scarcely  perceptible,  but  they  continue  to  grow 
in  all  j)arts  until  a  length  more  or  less  definite  for  the  sjiecies  is  attained, 
so  that  leaves  and  branches  become  separated  by  imiform  vertical  as 
well  as  circumferential  spaces.  This  brings  us  to  another  great  distinc- 
tion between  tli(>  stem  and  the  root,  in  which  latter  we  lia\-e  found  a 
contiiuions  and  uniform  longitudinal  de\elopnient. 

Axils  in  which  Buds  do  not  Develop.  The  rule  that  a  branch  de\eloi)s 
in  each  leaf-axil  is  habitually  (lc|)arted  from  in  the  leaf-representatives 
constituting  the  flower,  and  accidentally  in  sonic  other  cases.  Its 
failure  to  devel()|)  may  be  tem]jorary,  although  oftiMi  \-cr\  long  con- 
tinued, or  it  may  be  permanent. 


154  EXTENSIONS  AND  APPENDAGES  OF  THE  STEM 

Occasional  Failure  of  the  Leaf  to  Develop. — U])()n  the  other  hand,  the 
subtending  leaf  may  fail,  accidentally,  or  in  a  few  cases  habitually,  to 
develop,  so  that  the  branch  does  not  show  its  axillary  nature. 

Abnormal  Position  of  Branches. — Finally,  we  note  that  a  branch  may 
accidentally,  or  in  some  cases  habitually,  develop  from  some  other 
point  than  the  leaf-axil,  or  two  or  more  may  develop,  at  least  partially, 
from  one  axil,  either  side  by  side  or  in  a  vertical  row. 

Not  only  may  a  lateral  branch  thus  fail  to  develop,  but  the  apical 
extension  of  the  growing  point  may  fail,  accidentally  or  habitually, 
the  growth  being  continued  by  means  of  one  or  more  branches  only. 

Sympodial  and  Monopodial  Stems. — When  this  method  of  growth  is 
characteristic,  the  new  branch  taking  the  place  of  the  suppressed  stem 
which  produced  it,  at  each  successive  node,  so  that  the  stem  becomes 
composed  of  a  succession  of  one-jointed  branches,  the  stem  is  called 
Sympodial,  as  contrasted  with  the  term  Monopodial,  for  the  ordinary 
form,  in  which  the  apical  growth,  as  well  as  that  of  the  branches,  is 
continued  from  joint  to  joint. 

The  natural  result  of  such  a  series  of  branchings  would  be  to  produce 
an  angular  divergence  of  the  axis  at  each  joint,  as  the  branch  projects 
more  or  less  laterally  from  its  support.  This,  however,  is  usually  not 
the  case.  In  many  plants  the  new  branch  takes  the  erect  position  of 
that  which  it  has  replaced,  preserving  the  rectitude  of  the  axis,  and  so 
tending  to  obscure  the  sympodial  nature  of  its  growth.  In  such  cases, 
we  must  search  for  other  indications  of  its  nature.  This  subject  will  be 
understood  upon  reference  to  the  accompanying  diagrams  (Figs.  428 
to  430),  in  which  a  in  each  case  represents  the  apical  extension,  b  the 
leaf,  c  the  axillary  branch.  It  is  seen  that  the  positions  of  the  three, 
with  relation  to  each  other,  are  the  same  in  every  case,  the  axillary 
branch  being  between  the  other  two,  no  matter  what  changes  in  their 
directions  may  occur.  In  Fig.  429  the  apical  phytomer  has  been 
forced  a  little  to  one  side,  while  in  Fig.  430  it  has  become  perfectly 
horizontal,  the  branch  substituting  it  in  the  erect  position.  It  is  clear 
that  in  the  last  case,  c  might  easily  be  mistaken  for  the  main  stem, 
a  for  a  branch.  If  this  view  is  taken,  however,  we  are  at  once  met  by 
the  difficulty  that  the  supposed  branch  has  no  leaf  at  its  base,  that  is, 
it  is  not  axillary,  while  the  leaf,  b,  has  no  branch  in  its  axil.  Both  these 
difficulties  entirely  disappear  when  we  regard  the  body  between  the 
other  two  as  the  branch. 

A  mistake  becomes  even  more  easy  when  one  of  the  structures 
becomes  modified  into  some  unusual  form.     Thus,  in  Fig.  431,  the 


SYMPODIAL  AND  MONOPODIAL  STE.\fS 


155 


terminal  pliytonicr  has  become  converted  into  a  tendril  (a).  This 
tendril  must  be  a  modified  main  stem,  a  modified  l)ranch,  or  a  modified 
leaf,  and  the  decision  is  perfectly  easy  when  we  intjuire  as  to  its  relation 
to  tlie  axil.  In  Fig.  432,  where  the  apical  j)ortion  has  become  converted 
into  an  inflorescence,  followed  by  a  cluster  of  grapes,  the  determination 
is  the  same. 

In  all  these  ilhistrations  but  one  phytonier  witli  its  ])r()(hicts  is 
displayed.  By  viewing  a  series  of  them,  we  are  a})le  to  determine  a 
number  of  distinct  forms  of  the  sympodial  stem,  depending  upon  the 
order  of  its  branching.  In  Fig.  433  the  branches  are  borne  alternately 
upon  the  two  sides,  and  directed  alternately  to  right  and  left,  giving 


fffl*.1 


Figures  illustrating  sympodial  growth:  Fig.  428.  a,  superposed  phytonier;  I,  leaf;  c,  axillary 
phytomer  or  branch.  429.  o,  turned  aside;  b,  assuming  its  place.  430.  The  change  complete,  the 
superposed  phytomer  become  lateral,  standing  opposite  the  leaf.  431.  (The  grape)  same  positions  as 
in  430:  a,  metamorphosed  into  a  tendril.  432.  a,  converted  into  an  inflorescence.  433.  Alternating 
sympodial  growth.     434.   Unilateral  sympodial  growth.     435.     Bifurcating  sympodial  growth. 


a  flexuous  appearance  to  the  sympodium;  but  it  must  not  be  forgotten 
that  they  may  grow  quite  erect,  the  leaves  alternating  regularly  upon 
the  two  sides  and  the  stem  appearing  monopodial.  No  axillary  branches 
will,  however,  be  found.  In  Fig.  434  the  branches  develop  successively 
upon  the  same  side.  In  this  case,  also,  the  fully  developed  portion  of 
the  stem  is  straight  and  api)ears  monopodial,  exce])t  that  the  leaves 
are  all  upon  one  side  (secmul),  but  the  ])eculiar  direction  taken  by  the 
undeveloped  portion  toward  the  tip  indicates  its  true  nature,  as  well 
as  the  absence  of  axillary  branches.  Fig.  435  represents  a  sympodial 
stem  on  which  the  branches  are  borne  in  ])airs,  the  obvious  result  being 
a  double  symmetry,  each  branch  successively  ending  in   a  pair  of 


156 


EXTENSIONS  AND  APPENDAGES  OF   THE  STEM 


branches.  This  gives  us  the  forked  or  Bifurcating  form  of  sym])0(linm, 
often  called  (Hchotomous,  though  this  term  refers  strictly  to  one  in 
which  forking  is  caused  by  the  vertical  division  of  a  terminal  cell. 

Superficial  Appendages  to  Stems. — Besides  modified  or  unmodified 
leaves  or  branches,  stems  may  develop  various  other  ai)i)endages. 
When  these  are  merely  superficial,  they  are  called  Trichomes.  The 
characters  of  trichomes  upon  stems  or  leaves,  particularly  the  latter, 
are  of  the  utmost  importance  in  diagnosis.  Their  study,  however, 
save  as  to  the  surface  characters  which  they  collectively  produce, 
pertains  to  histology.  The  gross  surface  character  so  produced  will 
be  taken  up  in  connection  with  the  leaf. 


Fig.  430.  Aculeate  stem  of  Chadaea.      a,  hooked  prickles. 


Emergences  or  Outgrowths. — When  ai)pendages  are  of  deeper  origin 
they  are  called  Outgrowths  or  Emergences.  These  may  contain  vascular 
tissue,  connected  with  that  of  the  stem.  Outgrowths  are,  for  the  most 
l)art,  in  the  form  of  spines,  hooks  (Fig.  436,  a),  warts,  suckers  (Ing.  459, 
a,  in  this  illustration  a  modified  stem),  or  grasping  organs.  Usually 
organs  of  this  kind  are  the  results  of  modifications  of  other  organs, 
rather  than  outgrowths.  Both  trichomes  and  outgrowths  may  be 
regularly  or  irregularly  disposed. 


DUDS  157 

Roots  from  Stems. — Roots  may  develop  from  branches  which  are 
subterranean  or  which  rest  upon  the  surface  of  the  ground  or  are  high 
above  it.  Tlie  hitter  may  descend  and  enter  the  ground,  fix  themselves 
to  a  neighboring  body  for  sustenance  or  support,  or  both,  or  extend 
into  the  atmosphere.  'V\\v\  may  c\cn  turn  and  cntci-  a  (lisca>c(l  (ir 
decaying  ])()rti()n  of  their  own  ])lant.  They  normally  (h'xcloi)  from  the 
nodet)nly,  but  may  dcxclo])  from  any  other  ])art  or  ('\('n  fi-om  h'a\es. 

Buds. — An  undeveloi)e(l  stem  or  branch,  or  the  i)artially  developed 
summit  of  one,  is  a  Bud  or  Gemma.  The  bud  may  be  in  a  process  of 
continuous  development  of  its  lower  elements  into  mature  phytoraers, 
with  the  continuous  ])roduction  of  a  new  growing  point,  or  it  may 
pass  into  a  resting  state  between  successive  seasons  of  growth.  In 
the  latter  case  it  undergoes  special  modifications  (6  in  Figs.  447,  448, 
and  450).  Its  outer  leaves  become  developed  previous  to  the  resting 
stage,  but  not  as  foliage  leaves.  They  become  modified  instead  in 
various  directions  as  to  form,  proportions,  relative  position,  apjjend- 
ages,  and  exudations,  to  fulfil  tlie  office  of  protection  as  scales, 
and  they  subsequently  fall  away,  ne\cr  devel()i)ing  into  foliage  leaves. 
When  no  such  provision  is  made,  the  bud  is  commonly  destroyed,  with 
more  or  less  of  the  young  stem  tip  near  it,  during  the  resting  period. 
Occasionally  the  bud  is  protected  for  a  time  by  a  special  covering,  formed 
by  the  petiole  of  the  subtending  leaf.  It  is  then  called  a  Subpetiolar 
Bud. 


CHAPTER    XV 

CLASSIFICATION   OF  ROOTS  AND  STEMS 
CLASSIFICATION  OF  ROOTS 

Roots  may  be  classified  as  to  their  duration,  their  order  in  time  of 
development,  place  or  nature  of  origin,  function,  form,  and  consistency. 

Duration  of  Roots. — As  to  duration,  we  have  roots  divided  into  two 
great  classes,  although  the  terms  designating  them  are  in  general  applied 
to  the  plant  as  a  whole  rather  than  to  the  root.  Monocarpous  plants 
are  those  which  die  after  producing  one  crop  of  fruit;  Polycarpous, 
those  which  produce  successive  crops.  The  former  are  Annual  when 
they  live  but  a  single  season — as  the  rag- weed  and  the  sunflower; 
Biennial,  when  they  devote  the  first  season  to  the  storing  up  in  some 
receptacle,  such  as  a  fleshy  root  or  bud,  a  supply  of  nutriment,  and 
fruit  and  die  in  the  second  season.  The  term  winter-annuals  has  been 
applied  to  those  which  begin  their  life  during  the  latter  part  of  the  first 
season,  fruiting  early  the  next  season,  so  that  their  combined  life  during 
the  two  seasons  is  less  than  twelve  months,  as  in  the  case  of  wheat  and 
rye.  Such  may,  by  being  planted  early  in  the  season,  finish  their 
existence  during  one  season,  as  in  the  case  of  spring  wheat.  Those 
monocarpous  roots  which  devote  a  number  of  years  to  the  preparation 
for  fruiting,  as  in  case  of  the  century  plant,  belong  to  the  Perennials.  • 
All  Polycarpous  roots  belong,  of  course,  to  the  perennials. 

Order  of  Development. — Primary  and  Secondary  Roots. — As  to  their 
order  in  time  of  development,  the  first  root  developing  from  the  radical 
is  the  primary.  All  subsequently  developed,  whether  from  root  or 
stem,  are  secondary,  although  those  developing  from  secondary  roots 
are  sometimes  designated  Tertiary  and  so  on. 

The  Tap  Root. — If  the  primary  root  continue  its  development  so  as 
to  constitute  a  branch-bearing  axis,  it  is  called  a  Main-root  or  Tap-root 
(F'ig.  439).  The  ultimate  behavior  of  the  tap-root,  when  not  of  the 
fleshy- thickened  storage  class,  depends  upon  the  development  of  the 
leafy  crown  of  the  stem.  The  extent  of  root-growth  and  its  development 
will  agree  with  that  of  the  stem-crown.    Two  forms  of  stem-crown  are 


ORDER  OF  DEVELOPMENT 


159 


rcc'()f];nized,  the  one  liaviiiji;  its  l)raiiclie.s  and  leaves  so  disposed  as  to 
coiidiict  the  rain  whieh  falls  upon  them  in  toward  and  down  the  stem, 
the  other  condnctinjj;  it  outward,  so  as  to  fall  from  the  perijjhery.  An 
examination  of  the  former  elass  of  plants  may  be  expeeted  to  diselose 
a  ta])-r()()t  which  maintains  a  \ertical  downward  direction,  its  branching 
not  hein^'  wide.  TJiose  of  the  second  class  will  generally  he  found  to 
ha\c  their  tajj-roots  (piickly  dividing  u])  into  innncrous  horizontal 
branches  which  bear  the  greater  part  of  their  small  absorbing  rootlets 
around  the  perii)hery,  just  where  they  will  catch  the  droppings  from  the 
peri])hery  of  the  leafy  crown. 


Fig.  437.  Tubercles  of  Jalap.  438.  Death  of  first  portion  of  stem,  it.s  subsequent  growth  maintained 
by  cluster  of  secondary  roots.  439.  Tap-root,  with  branches,  of  .4 TO6ro.sia,  440.  Underground  portion 
of  potato  plant:  a,  tubers;  h,  rhizomes,  the  roots  seen  intermingled.  441.  A  napiform  fleshy  root. 
442.   Fusiform.     443.  Conical. 


The  "Multiple  Primary  Root.'' — If  the  primary  root  of  a  very  young 
plant  divide  at  once  into  a  number  of  approximately  equal  branches, 
it  constitutes  the  so-called  ]\Iultiple  Primary  Hoot.  This  term  has, 
however,  been  applied  to  a  number  of  root-dusters  of  similar  appear- 
ance, but  of  very  dissimilar  origin.  In  some  cases  the  primary  root 
continues  its  vertical  growth  but  does  not  increase  in  thickness  to  any 
a])preciable  extent.  A  number  of  similar  roots  then  develoj)  near  its 
l)oiiit  of  origin,  so  that  a  fascicle  of  similar  I'oots  at  length  results,  as  in 
the  onion.  In  other  eases  a  prostrate  stem  takes  root  from  one  of  its 
nodes,  the  j)()rtion  below  this  point  (Fig.  438,  a),  with  the  original  roots. 


160  CLASSIFICATION  OF  ROOTS  AND  STEMS 

perishing.  To  the  ckister  of  roots  thus  resulting,  although  they  are 
really  secondary,  the  term  "multiple  primary"  has  also  been  applied. 
A  true  multiple  primary  root  is  of  rare  occurrence  and  does  not  exist 
among  drugs. 

Adventitious  Roots.— AW  roots  which  are  not  primary,  or  branches 
thereof,  and  all  branches  of  roots  which  are  not  de\'eloped  in  regular 
order  of  succession,  are  called  Adventitious. 

Place  and  Nature  of  Origin. — Subterranean  and  Aerial  Roots. — As  to 
their  place  and  nature  of  origin,  roots  are  Subterranean  when  they 
originate  from  points  underground,  whether  from  root  or  stem,  and 
Aerial  when  they  originate  from  points  above  the  surface,  whether  from 
root  or  stem.  A  root  may  originate  from  an  aerial  point  and  afterward 
fix  itself  in  the  earth,  as  the  Brace-roots  of  maize. 

Fascicled  Roots. — A  number  of  approximately  equal  and  similar 
roots  occurring  in  a  cluster,  especially  if  they  be  fleshy-thickened,  are 
denominated  Fascicled. 

Fibrous  Roots. — Roots  existing  in  the  form  of  a  mass  of  thin,  fiber- 
like, approximately  equal  and  similar  elements  are  called  Fibrous 
(Fig.  446). 

Functions  of  Roots. — As  to  their  functions,  roots  are  known  as  Absorb- 
ing, Fixing,  and  Storage  roots.  A  root  of  one  kind  may  give  origin  to  a 
branch  of  a  different  kind. 

Haustoria. — Absorbing  roots  of  parasitical  plants  are  frequently 
greatly  modified  in  structure  to  form  Haustoria. 

Rhizoids. — Fixing  roots  are  usually  designated  as  Rhizoids. 

Storage  Roots  are  usually  much  enlarged  and  possess  a  fleshy  con- 
sistency and  characteristic  forms  (Figs.  441  to  443). 

Tubercles. — When  only  a  limited  portion  of  a  root  is  fleshy-thickened, 
so  as  superficially  to  resemble  a  tuber,  it  is  called  a  Tubercle,  as  the 
Jalap  (Fig.  437).  Care  should  be  taken  not  to  confuse  this  technical 
meaning  of  the  term  with  its  common  use  as  designating  a  small  tuber. 

Forms  of  Roots. — As  to  their  form,  roots  are  simple,  when  they  do  not 
branch,  or  Branched,  Cylindrical,  Terete  (which  includes  the  cylindrical 
and  that  form  which  differs  only  in  that  it  tapers),  Xapiform,  when 
taking  the  form  of  a  short,  broad  turnip  (Fig.  441),  Fusiform  when 
spindle-shaped,  as  some  radishes  (Fig.  442),  Conical  or  Cone-shaped 
(Fig.  443),  Capillary  when  very  thin,  long  and  'hair-like. 

Consistency  of  Roots. — Woody  and  Fleshy  Roots. — As  to  consistency, 
they  are  denominated  as  Woody  and  Fleshy.  By  "fleshy"  or  "non- 
woody"  we  do  not  mean  that  wood  tissue  is  entirely  lacking,  but  rather 


nruMios  101 

tliat  the  })r()i)()rti{)ii  of  the  (rllulnr,  paroiidiymatic,  or  fiesliy  elements 
is  so  mueh  <]jreater  than  that  of  the  woody  that  a  woody  eharaeter  is  not 
apparent.  In  practical  pharmacognosy,  where  dried  roots  are  mostly 
observed,  a  number  of  other  terms  for  consistency,  as  in  the  case  of  the 
hark,  come  into  use. 

CLASSIFICATION  OF  STEMS 

Stems  may  he  chissified  as  to  duration,  order  of  d('\ cloiJinciit  in  time, 
position,  and  nature  of  origin,  mode  of  extension,  direction  of  ii;rowth 
and  nature  of  sup])ort,  modification  of  form  or  function,  and  consistence. 

Duration. — As  to  duration,  they  are,  like  roots,  Annual,  Biemiial,  and 
Perennial. 

Ilrrhs. — Annual  stems  are  those  which  die  at  the  close  of  the  season. 
They  may  or  may  not  i)ertain  to  annual  roots.  Plants  possessing  them 
are  called  Herbs.  Herbs  are  therefore  either  Annual,  Biennial,  or  Per- 
ennial, in  accordance  with  the  character  of  the  root,  but  their  stems 
are  always  annual.  The  definition  of  an  herb  is  a  plant,  the  aerial 
portion  of  which  dies  at  the  season's  close.  The  stem  of  an  herb  is 
denominated  Herbaceous. 

Biemiial  Stems. — Biennial  stems  are  those  which  are  jjroduced, 
usually  underground  like  that  of  the  potato  (Fig.  440,  b),  during  one 
season,  and  perish  after  the  production  of  their  branches  in  the  following 
season.  Occasionali\",  howexcr,  like  the  cabbage,  a  biemiial  stem  is 
aerial. 

Tubcn'. — Fleshy-thickened  and  biennial  portions  of  niidcrgronnd 
stems,  such  as  the  ])()t;ito,  ai'c  denominated  Tubers  (Fig.  410,  (i).  l''ig. 
444  represents  tiic  undei-ground  poi-tion  of  the  ('iirciniKi,  and  well 
displays  the  dill'erence  between  tubers  and  tubercles. 

Bulbs. — Basal  biennial  portions  of  stems  which  are  invested  by  more 
or  less  fleshy-thickened  storage-leaves  are  called  Bulbs.  J5ulbs  will  be 
classified  under  the  subject  of  buds. 

Perennial  Stems. — Perennial  stems  are  those  which  Wvv  and  extend 
their  growth  from  year  to  year.  They  are  Determinate  when  their 
growth  of  the  season  is  self-limited  and  closes  with  the  production  of  a 
sj)ecially  i)repared  Winter-bud,  which  protects  the  growing  point  for 
continued  growth  tlie  next  season;  Indeterminate,  when  no  such  bud 
is  formed,  growth  contimiing  until  the  aj)ical  portion  is  destroyed  by 
an  incl(Mnent  season.  In  the  latter  class  we  have  the  anomaly  of  a 
])ereiiiiial  stem  with  an  annual  ti[). 
11 


162 


CLASSIFICATION  OF  ROOTS  AND  STEMS 


Order  of  Development. — Primary  and  Secondary  Stems. — As  to  their 
order  of  fle\elopment  in  time,  stems  are  Primary,  Secondary,  and  so 
on,  terms  which  are  self-explanatory. 

Place  and  Nature  of  Origin, — Aerial  and  Subterranean  Stems. — As  to 
their  j)()sition  and  nature. of  origin,  stems  are  Aerial  or  Subterranean, 
which  terms  are  also  self-explanatory.  A  secondary  stem  assuming  an 
erect  position  from  the  base  of  the  primary,  like  those  of  the  Indian 
corn,  is  a  Sucker.  Such  an  one  arising  from  a  rhizome  at  a  considerable 
distance  from  the  original  erect  stem,  as  in  the  blackberry,  is  called  a 
Stolon.  A  short  secondary  stem  developing  from  the  base  of  the  primary 
is  called  an  Offset.  An  elongated,  slender  one,  lying  prostrate  and 
rooting  at  some  of  its  joints,  is  called  a  Runner  (Fig.  445). 


Fig.  444.  Tubers  of  Curcuma. 


44S. 


445.  Runner  of  strawberry  plant, 
scaly  rhizome  of  Gesneria. 


446.    Fibrous   roots   attached   to 


The  Rhizome. — An  underground  stem,  fleshy-thickened  at  least  during 
the  first  year,  so  as  to  serve  as  a  storage  receptacle,  and  giving  origin 
to  an  aerial  summit  or  branch,  is  a  Rhizome  (Figs.  447  to  452). 

Distinctions  betiveen  the  Rhizome  and  the  Root. — A  rhizome  is  very 
frequently  mistaken  for  a  root,  but  the  differences,  both  internal  and 
external,  are  well-marked.  The  internodes  of  the  rhizome  are  com- 
monly quite  as  uniform  in  length  as  those  of  the  aerial  stem.  The  nodes 
are  usually  conspicuous.  Leaves  exist  upon  them,  commonly  in  the 
form  of  scales.  Occasionally  these  scales  are  numerous  and  well  formed 
(Fig.  446),  but  usually  they  are  rather  obscure,  as  in  the  potato,  where 
they  are  mere  semicircular  or  crescent-shaped  ridges  about  the  eyes. 
In  the  axils  of  the  scales,  buds  are  usually  to  be  distinguished.  These  are 
the  so-called  "eyes"  of  the  potato,  and  their  develoi)ment  into  branches 
is  a  familiar  phenomenon.  Internally,  the  structure  of  the  rhizome  is 
in  general  that  of  the  stem,  though  fleshy  tissue  predominates. 

The  growth  and  duration  of  a  rhizome  may  be  indefinite,  like  those  of 
stems,  as  in  the  case  of  the  rhizome  of  Podophyllum  (Fig.  449),  or  they 
may  be  restricted  to  one  or  to  a  definite  number  of  }ears,  after  which  the 


PLACE  AND  NATURE  OF  nUKlIN 


163 


oldest  existing;  ])liyt()nu'r  ])erislios  each  year  as  a  suceessi^■e  a])ical  one 
is  formed  (Fij;.  450,  h). 

Forms  of  Rhizomes. — Rhizomes  are  so  inimeroiis  and  important  in 
pharmacy  that  their  characters  call  for  special  attention.  They  are 
classed    as    short    or    elongated,  the    former    term    referring   to  those 


4S2. 


Forms  of  rhizomes:  Fig.  447.  Convallariti,  with  :iiiiiular  roots:  «,  terminal  l)ii<l.  448.  Cimicifiii/n, 
its  cup-shaped  stcni-scars  much  elevated.  449.  Podophyllum,  its  intcrnodes  elongated.  450.  Poly- 
poria/UOT,  its  cup-shaped  scars  depressed.  451.  /n's,  its  roots  aggregated  at  one  end.  452.  Acorus,  with 
V-shaped  leaf-soars. 


the  extreme  length  or  shortness  of  which  fall  within  certain  fairly 
defined  and  restricted  limits;  the  latter,  those  which  cither  j^ossess  an 
indefinite  extension,  or  the  definite  length  of  which  is  a  great  many 
times  their  thickness.  Terms  indicati\e  of  their  form  and  consistency 
do  not  differ  materially  from  those  a])i)lied  to  other  stems  and  to  roots. 
They  are  almost  always  sympodial.    They  are  very  subject  to  flatten- 


164  CLASSIFICATION  OF  ROOTS  AND  STEMS 

ing,  the  flattened  surfaces  usually  looking  upward  and  downward.  The 
presence  or  absence  of  branches  is  always  characteristic.  The  manner 
in  which  the  roots  take  their  origin  is  c(|ually  so.  These  may  form  a 
circle  (Fig.  447)  or  be  restricted  to  the  under  surface  (Fig.  449).  The 
number  of  roots  developing  from  a  node  is  usually  fairly  characteristic. 
So  is  the  persistency  or  brittleness  of  these,  and  the  characters  of  the 
stumps  or  scars  which  they  leave,  as  well  as  their  form,  which  is  very 
often  triangular  or  quadrangular  in  section.  Their  structure,  as  observed 
either  with  the  lens  or  with  the  microscope,  is  characteristic  and  of 
diagnostic  value.  Sometimes  the  roots  are  not  only  restricted  to  a 
certain  portion  of  the  node,  but  in  the  case  of  short  rhizomes  are  re- 
stricted to  a  definite  portion  of  the  latter  (Fig.  451).  The  relative  length 
of  the  internodes  of  a  rhizome,  as  compared  with  its  diameter  or  thick- 
ness, calls  for  close  attention,  and  so  does  the  absolute  or  measured 
length.  The  relations  of  the  erect  portions  to  the  horizontal,  and  the 
stumps  or  scars  left  by  the  former  upon  their  death  or  separation,  con- 
stitute one  of  their  most  important  diagnostic  characteristics.  Com- 
monly, disarticulation  occurs,  with  the  production  of  a  cup-shaped  scar. 
This  scar  will  be  characteristic  as  to  whether  it  form  a  depression  in  the 
general  surface  (Fig.  450)  or  be  elevated  upon  a  base  (Fig.  448),  as  will 
the  length  of  the  latter,  the  form  and  depth  of  the  scar,  and  the  char- 
acter of  its  edge.  The  size  of  the  scar,  that  is,  its  lateral  breadth  as 
compared  with  the  thickness  of  the  internode,  is  also  noteworthy. 
Leaf  scars,  or  leaf  remains,  upon  rhizomes  call  for  the  same  examination 
as  do  the  stem  scars.  They  may  surround  the  entire  rhizome,  in  which 
case  they  are  designated  Annular,  or  they  may  be  confined  to  the  upper 
surface.  If  the  latter,  the  scar  may  be  of  characteristic  form,  as  linear, 
elliptical,  circular,  cordate,  crescent-shaped,  or  ^"-shaped  (Fig.  452,  a). 
Finally,  we  note  that  annular  or  longitudinal  folds,  thickenings,  wrinkles, 
or  constrictions  are  characteristic  of  certain  rhizomes  as  well  as  of  roots, 
particularly  in  the  dried  state. 

Mode  of  Extension. — Simple  and  Branched  Stems. — As  to  their  mode  of 
extension,  stems  may  be  Simple  or  Branched.  A  stem  denominated  as 
simple  is  not  necessarily  entirely  destitute  of  branches,  as  floral  branches 
or  small  branches  near  the  summit  are  permitted.  It  has  already 
been  shown  that  stems  may  develop  monopodially  or  sympodially. 
The  stem  of  a  tree  which  continues,  except  in  case  of  accident,  to  develop 
monopodially,  as  the  Fir,  is  called  Excurrent.  One  which  after  a  time 
loses  its  main  stem  in  a  number  of  branches,  as  for  instance  the  elm,  is 
Deliquescent. 


MODIFICATION  OF  FORM  OR  FUNCTION  1G5 

Acauh'scent  Plants. — The  term  Acaiileseent,  wliile  strictly  meaning 
stemless,  can,  of  course  have  no  such  ai^phcation,  as  all  fiowering  plants 
possess  a  stem,  even  before  germination  occurs.  The  term  is  applied 
to  those  plants  whose  stems  arc  so  short  as  not  to  become  con- 
si)icu()us. 

The  Crou'ii. — The  stem  of  sudi  a  plant  is  called  a  ("rowii.  The  term 
crown  is  also  appUeil  to  the  branching  or  leafy  portion  of  any  stem. 

Trees,  Shrubs,  and  Vudcrshruhs. — A  plant  possessing  a  woody  and 
erect  stem  rising  singly  to  the  height  of  fifteen  (according  to  some 
authorities,  twelve)  feet  or  more  is  denominated  a  Tree,  or  Arborescent 
plant,  although  the  precise  application  of  such  a  term  is  impossible. 
A  perennial  woody  stem  which  has  not  these  characters  is  called  a 
Shrub  or  a  Fruticose  stem.  Very  small  shrubs  appearing  on  causal 
insi)cction  as  herbs  are  called  Undershrubs  or  Suffruticose  plants. 

Direction  of  Growth  and  Nature  of  Support. — As  to  the  direction  of  their 
growth  and  the  nature  of  their  supjjort,  stems  may  be  Erect,  in  which 
case  they  are  erect  through  their  entire  length;  Ascending,  in  which  case 
the  base  for  a  greater  or  less  distance  rests  upon  the  ground,  the  terminal 
portion  becoming  erect;  Horizontal,  in  which  case  they  are  considered 
as  having  no  other  support  than  the  parent  stem,  from  which  they 
extend  at  a  right  angle;  Drooping,  in  which  case  they  are  first  hori- 
zontal, the  outer  portion  becoming  pendant;  Pendant,  or  "Weeping," 
when  they  are  pendulous  from  their  point  of  origin  or  almost  therefrom; 
Decumbent,  when  at  first  erect  or  supported  by  the  i)arent,  the  outer 
l)()rtion  dechned  so  far  as  to  rest  upon  the  ground;  Reclining,  when 
resting  ui)on  some  means  of  sui)i)ort  elevated  above  the  earth,  as  over 
the  t()i)s  or  branches  of  other  i)lants;  ProcnmlxMit,  when  resting  at  full 
length  upon  the  ground  witlioiit  rooting  at  the  joints;  Repent,  or 
"Creeping,"  when  ])rostr;itf  and  rooting  at  the  joints  (Fig.  445); 
Twining,  when  sup])orting  themselves  by  the  twining  of  the  stem  itself 
around  a  support;  Climbing,  when  elevating  and  sui)porting  them- 
selves by  other  methods  than  a  twining  habit,  the  principal  forms  being 
the  Cirrhiferous,  when  climbing  by  tendrils  (Fig.  4;-51),  and  Aculeate, 
when  cliinbiiig  i)y  hooks  (Fig.  4;]()). 

Modification  of  Form  or  Function. — Mixli/ird  Sfews. — As  to  modifi- 
cation of  form  or  function,  stems  arc  snbj(>ct  to  a  somewhat  elaborate 
classification. 

They  may  be  modified  for  the  ])uri)osc  of  defence,  that  is  into  thorns 
or  spines  (Fig.  l.").'i),  altliongli  not  all  thorns  or  spines  arc  transformed 
branches.     Some  branches  of  this  foi'ni  remain  so  permani-ntly,  while 


IGG 


CLASSIFICATION  OF  ROOTS  AND  STEMS 


others  become  foliaceous  later  and  de\'elop  into  branches  of  the  ordinary 
form  (Fig.  454). 

For  the  purpose  of  cHmbing,  they  may  become  cirrhose,  that  is, 
converted  into  Tendrils.     The  tendril  may  consist  of  the  apex  of  the 


^6. 


Illustrating  modified  stems:  Fig.  453.  Branch  converted  into  thorn.  4.54.  The  same  becoming  leafy. 
455.  Branch  of  Strychnos,  becoming  a  tendril.  456.  Stem  of  Lemma,  modified  like  a  leaf.  457. 
Branches  of  a  species  of  Asparagus,  modified  as  leaves.  458.  Condensed  stems  of  Opuntia.  459. 
Branches  of  Ampelopsis  metamorphosed  into  disks.  460.  Branches  of  Phyllanthus,  modified  like 
leaves,  but  flower-bearing. 

primary  stem  (Fig.  431),  or  one  of  the  branches  may  become  the  tendril, 
as  in  Strychnos  (Fig.  455).  In  the  latter  case  the  tendril  will  stand  in 
the  axil  between  leaf  and  stem;  in  the  former  it  will  stand  upon  the 
opposite  side  of  the  stem  from  the  leaf,  for  reasons  already  explained. 
A  stem  may  instead  become  converted  into  a  sucking  disk,  as  in  the 


MODIFICATION  OF  FORM  OR  FVSCTION  167 

case  of  Ami)eloi>sis  (Fig.  459,  a).  In  this  case  the  tip  of  tlie  branch  or 
stem  becomes  flattened  and  attaches  itself  very  tightly  to  the  supporting 
surface;  so  tightly,  in  fact,  that  a  portion  of  stone  or  a  splinter  of  wood 
may  be  torn  from  its  support  before  the  disk  can  be  made  to  separate 
from  it.  Plants  which  grow  in  the  water  or  in  places  subject  to  inunda- 
tion may  have  portions  of  their  stems  inflated  into  bladdery  forms  to 
insure  a  floating  condition.  Such  structures  are,  however,  more  com- 
monly of  a  leafy  nature. 

Cladoidia  or  Cladophylla.- — Stems  may  become  modified  for  the  j^er- 
formance  of  the  office  of  leaves.  Such  a  stem  is  called  a  Cladoidium  or 
Cladophyllum  (Figs.  457  and  400).  For  this  purpose  the  whole  stem 
may  become  modified  into  a  single  leaf-like  organ,  as  in  the  case  of 
certain  aquatics,  in  which  case  it  is  known  as  a  Frondose  Stem  (Fig. 
456).  Upon  the  other  hand,  separate  portions  of  the  stem  or  separate 
branches  thereof  may  become  thus  modified,  as  in  the  case  of  the  so- 
called  "leaves"  of  the  species  of  Asparagus  cultivated  as  a  decorative 
plant  under  the  name  of  Smilax  (Fig.  457:  a,  leaf;  6,  branch).  Some- 
times a  stem  or  a  joint  of  one,  at  the  same  time  that  it  becomes  modified 
to  perform  the  office  of  a  leaf,  performs  the  ordinary  offices  of  a  stem, 
or  important  storage  functions  as  well,  as  in  the  case  of  the  Opnntia 
(Fig.  458),  and  the  Phyllanthus  (Fig.  400).  Such  stems  are  called 
Consolidated.  Branches  like  those  in  Fig.  400,  modified  to  perform 
the  leaf-function,  are  called  PhyUocIadia. 

]\Iany  trees  have  been  encountered  by  the  author  in  troj)ical  America, 
the  stems  and  branches  of  which  are  hollow  (denominated  fistulous), 
afl'ording  permanent  homes  to  myriads  of  ants,  which,  deriving  their 
sui)port  from  the  tree,  are  supposed  to  confer  some  compensatory 
benefit  upon  it.  They  at  least  protect  the  tree  against  animal  attacks, 
being  in  all  cases  extremely  savage  and  venomous. 

Besides  such  specially  modified  forms,  a  number  of  ordinary  forms 
are  characterized  by  the  adjectives  Terete,  Cylindrical,  Compressed, 
Triangular,  Quadrangular,  Alate  or  Winged,  Costate  or  Ribbed,  Chan- 
nelled, Striate,  and  so  on.  In  this  connection  the  terms  a])plicable  to 
the  superficial  characters  of  barks  already  described,  and  those  con- 
nected with  leaf-attachment,  to  be  described  farther  on,  should  be 
studied.  In  addition  to  the  above-mentioned  stem-forms,  which  admit 
of  ready  classification,  we  have  a  large  number  of  modifications  to  efi'ect 
special  purposes,  which  must  be  considered  individually.  As  these 
])ossess  but  a  slight  interest  in  relation  to  pharmacognosy,  we  refer  the 
interested  student  to  more  general  works  on  botany. 


168 


CLASSIFICATION  OF  ROOTS  AND  STEMS 


Storage  Stems. — An  important  office  of  the  stem  is  the  storage  of 
nutriment.  All  stems  perform  this  office  to  a  greater  or  less  extent, 
but  some  are  especially  modified  in  form  for  the  purpose.  Of  these,  we 
have  already  specially  referred  to  rhizomes  and  tubers. 

The  Bulb. — It  remains,  then,  only  to  consider  the  various  forms  of 
the  bud,  including  in  this  term  all  forms  of  the  bulb.  A  bulb  which, 
like  the  onion  (Fig.  462),  has  its  fleshy-thickened  leaves  in  the  form 
of  broad  sheathing  organs,  seen  upon  transverse  section  in  the  form 
of  concentric  rings,  is  called  Tunicated  or  Coated.  Those  like  the  lily 
(Fig.  461),  in  which  these  leaves  appear  in  the  form  of  narrower  pro- 
jecting scales,  are  called  Scaly.     When  in  the  axils  of  the  scales  we  find 


Fig.  461.    Scaly   bulb  of   Lilium.     -iC^.    Tunicated   bulb   of  onion.     463.    Corm  of   Gladiolus.     464. 
Axillary  bud-bulb  of  tiger  lily.    465.  Terminal  head  of  bulbs  of  onion. 


smaller  or  secondary  bulbs  or  buds,  as  in  the  garlic,  it  is  a  Compound 
bulb.  When  the  texture  of  a  bulb  is  so  dense  that  its  leaf-elements  are 
not  conspicuous,  it  is  designated  as  a  Solid  bulb.  When  it  is  still  more 
dense,  as  in  the  case  of  the  Gladiolus  (Fig.  463),  so  that  the  leaves  are 
not  to  be  distinguished  by  ordinary  methods,  it  is  a  Corm.  In  some 
plants,  the  axillary  bulbs,  instead  of  occurring  in  the  axils  of  the  bulb- 
leaves,  occur  higher  up  in  the  axils  of  the  ordinary  foliage-leaves,  as  in 
the  case  of  the  tiger  lily  (Fig.  464).  Their  true  nature  as  buds  is  in 
this  case  conspicuously  shown,  and  they  are  sometimes  spoken  of  as 
Bud-bulbs.  In  other  related  plants,  similar  bulbs  are  densely  aggre- 
gated in  a  terminal  umbel  looking  like  an  inflorescence,  as  in  some 
species  of  onion  (Fig.  465). 


CLASSES  OF  BUDS  109 


CLASSIFICATION  OF  BUDS 


Buds  ])ro])er  admit  of  an  elaborate  elassifieation,  whieh,  although  not 
of  such  interest  in  pharmacognosy  as  to  warrant  its  study  here,  is  of 
fundamental  im})()rtance  in  systematic  botany,  and  furnishes  a  key  to 
many  ])roblems  which  are  otherwise  abstruse. 

Vernation  and  Praefoliation. — The  study  of  buds  is  called  A'ernation, 
and  that  of  the  arrangement  of  the  leaves  composing  them  Praefoliation. 
In  general,  the  arrangement  of  leaves  in  the  bud  admits  of  the  use  of 
terms  similar  to  those  ai)plied  to  the  parts  of  the  perigone  in  a  similar 
state. 

Classes  of  Buds. — Buds  may  be  classified  as  to  their  structural  form, 
their  position,  and  parts.  A  winter  bud  which  protects  itself  by  specially 
developed  scales  is  known  as  a  Scaly  bud;  one  which  does  not,  a  Naked 
bud.  A  bud  consisting  only  of  leaves  is  a  Leaf  bud ;  one  only  of  a  flower, 
a  Flower  bud;  one  consisting  of  both,  a  INIixed  bud.  Solitary  l)uds 
occurring  in  the  axil  of  the  leaf  and  developing  at  the  regular  time  are 
called  Normal  buds.  Any  buds  in  addition  to  the  normal  bud,  occurring 
in  the  leaf  axil,  are  called  Supernumerary.  They  may  be  situated  above 
or  at  the  side  of  the  normal  bud.  The  normal  bud  is  sometimes  situ- 
ated a  little  above  the  actual  axil,  in  which  case  it  is  called  Supra-axillary. 
All  the  buds  here  noted  are  denominated  Lateral,  in  contradistinction 
to  the  single  terminal  bud,  but  it  is  to  be  noted  particularly  that  buds 
lateral  as  to  their  origin  may  become  terminal  through  the  effects  of 
sym))()dial  growth.  Buds  which  dcNelop  at  other  points  than  the  aj)ex 
or  axil-  as,  for  instance,  fi'oin  an  internode,  a  leaf,  or,  rarely,  even  from 
a  root,  as  well  as  those  of  axillary  origin,  but  developing  out  of  their 
regular  order — are  called  Adventitious.  The  latter  form  of  aihen- 
titi(nis  buds,  when  I'csulting  from  retarded  dcNcloitnieiit,  are  know  n  as 
Latent  buds. 


CHAPTER    XVI 

THE   LEAF 

Importance  of  Leaf-study. — To  the  pharmacognosist  a  thorough 
knowledge  of  the  leaf  is  a  necessity.  Of  its  cellular  structure,  little  can 
be  learned  without  the  aid  of  the  compound  microscope.  Its  gross 
parts  were  briefly  referred  to  in  our  opening  chapter,  and  these  must 
now  be  studied  in  detail. 

Development  of  the  Leaf. — The  varied  forms  of  structure  which  leaves 
present  can  best  be  understood  by  considering  them  as  modifications  of 
an  original  or  primary  leaf  and  noting  the  changes  in  the  latter  which 
have  occurred  to  produce  them.  It  is  apparent  that  such  a  primary 
leaf  was  a  mere  scale  of  small  size,  as  indicated  in  Fig.  466.  It  then 
appears  that  any  modern  foliage  leaf  must  have  resulted  either  from 
the  uniform  growth  and  development  of  all  the  parts  of  such  a  scale,  or 
from  the  greater  relative  growth  of  some  one  or  more  of  its  parts.  The 
result  of  its  luiiform  growth  would  be  a  leaf  of  the  same  form,  but  larger, 
its  base  sheathing  the  stem,  as  represented  in  Fig.  467.  But  leaves  of  this 
exact  character  are  rare,  from  which  it  would  appear  that  modern  leaves 
generally  represent  unequal  degrees  of  development  of  the  different 
parts  of  the  original  leaf.  Their  attentive  examination  shows  that  the 
following  parts  of  such  a  primary  leaf  have  in  different  cases  undergone 
independent  enlargement  and  development.  In  Fig.  468,  the  portion  a, 
cut  off  by  the  dotted  line  at  the  top,  may  represent  the  Apical  region; 
that  at  h  the  Central-basal;  the  strip  a-h  the  axial;  and  the  remaining 
portions  upon  either  side  (c  and  d)  the  lateral.  Let  us  assume  first  that 
the  enlargement  is  confined  chiefly  to  the  central-basal  portion.  The 
base  will  then  become  converted  into  the  form  represented  in  Fig.  469, 
without  the  enlargement  of  the  other  parts  there  shown,  this  leaf  being 
a  mere  sheath  around  the  stem,  bearing  the  original  scale  at  its  tip. 
Leaves  of  this  form  are  rather  common  upon  undeveloped  or  partly 
developed  stems.  They  are  called  Leaf-sheaths,  or  often,  for  emphasis, 
Naked  Sheaths.  The  edges  of  such  a  sheath  may  cohere  after  passing 
around  the  stem,  giving  us  the  Closed  Sheath,  as  in  the  sedges  {a,  in  Fig. 
465  B),  or  they  may  remain  free,  giving  us  the  Open  Sheath  of  the 


DEVELOPMENT  OF   THE  LEAF 


171 


grasses  {a,  in  Vv^.  4().5  A).  Instead  of  passin^^  around  the  stem,  tlie 
edges  may  come  together  between  the  leaf  and  the  stem,  so  as  to  produce 
a  hollow  tube,  as  in  the  Sarracenia.  Let  it  next  be  assumed  that  the 
apical  portion,  as  well  as  the  central-basal,  enlarges,  with  little  enlarge- 
ment of  the  axial  or  lateral  portions.  We  shall  then  get  a  form  in  which 
a  Lamina,  or  Leaf-blade,  is  superposed  directly  upon  a  Leaf-sheath, 
Such  a  leaf,  expanded,  would  appear  as  in  Fig.  470,  if  the  blade  were 


46SA.  465 B.    4Y0.        47/ 


4r2 


Figures  illustrating  the  origin  and  development  of  the  parts  of  the  leaf:  Fig.  465  .-1.  The  grass-leaf: 
a,  the  open  sheath;  h,  the  ligulc.  4()o  B.  Tlie  sedge-leaf:  a,  the  closed  sheath.  466.  The  primordial 
leaf,  a  mere  scale.  467.  The  same,  as  equally  developed  in  all  parts.  4GS.  The  same,  divided  into  its 
different  regions:  o,  the  apical  portion;  b,  basal  portion;  c  and  d,  lateral  portions  with  axial  portion 
between.  469.  The  same,  undeveloped  except  the  basal  portion,  which  becomes  a  sheath  to  surround 
the  stem.  470.  The  same,  with  the  apical  portion  also  developed  to  form  a  blade,  the  lateral  and 
axial  portions  undeveloped.  471.  The  same,  with  the  lateral  portions  developed  into  stipules.  472. 
The  stipules  with  their  inner  margins  connate  between  the  blade  and  stem,  their  outer  connate  around 
the  stem,  forming  an  upper  sheath  or  ochrea.  In  40.5  .1  they  are  connate  only  by  their  inner  margins, 
between  blade  and  stem,  forming  the  ligule.    (Ailaptid  from  work  of  A.  A.  Tyler.) 

but  little  developed,  or  it  inight  be  deNcloped  e(nially  in  botli  ]iarts. 
Both  of  these  forms  are  fre(piently  encountered.  If  now  the  hiteral 
portions  shall  enlarge,  the  axial  jjortioii  not  imich  elongating,  a  lateral 
appendage  must  result  at  the  base  ui)on  eitiier  side,  as  in  Fig.  471. 
These  are  the  Stipules.  If  the  stipules,  insteatl  of  existing  separately 
in  this  way,  shall  incline  together  between  the  stem  and  the  leaf,  and 
their  inner  edges  cohere,  it  is  clear  that  they  must  form  a  small  blade 


172  THE   LEAF 

standing  out  upon  the  face  of  the  leaf  at  its  base,  as  h  in  Fig.  465  A. 
This  is  the  Ligule.  The  free  edges  of  the  Hgule  may  now  pass  around  the 
stem,  meeting  and  cohering  upon  the  other  side,  thus  forming  a  sheath 
above  the  basal  portion,  or  true  sheath  (Fig,  472).  Such  a  sheath  is 
called  an  Ochrea.  If,  lastly,  it  be  assumed  that  the  axial  portion  a-h 
(Fig.  468)  undergo  an  elongation  much  greater  in  proportion  than  the 
enlargement  of  the  other  parts,  we  shall  ha\e  developed  a  long  narrow 
division  between  the  base  and  the  lamina,  as  c  in  Fig.  3,  which  is  the 
Petiole.  It  is  thus  seen  that  the  view  here  taken  will  account  for  the 
origin  of  every  part  of  the  leaf.  The  few  illustrations  here  shown  refer 
only  to  certain  combinations  in  the  development  of  the  difi'erent  parts. 
As  a  matter  of  fact,  such  combinations  found  among  existing  leaves  are 
innumerable,  and  this  variety  is  increased  by  the  fact  that  the  growth  in 
any  one  of  these  parts  may  be  chiefly  lateral  or  chiefly  vertical,  and 
that  it  may  be  confined  wholly  or  chiefly  to  some  special  portion  of 
the  part.  The  student  will,  nevertheless,  be  able,  by  bearing  in  mind 
the  typical  possibilities  here  considered,  to  determine  the  plan  of  struc- 
ture of  most  leaves.  This  view  will  also  make  clear  the  statement  in  the 
opening  chapter  in  regard  to  the  absence  of  the  blade,  petiole,  or  other 
parts  from  certain  leaves. 

It  is  interesting  to  note  here  that  there  is  ample  evidence  to  prove 
that  the  rudimentary  or  scale-like  form  of  leaves  existed  upon  the 
earliest  flowering  plants,  so  it  would  appear  that  the  parts  of  their 
flowers  were  developed  from  such  scale-leaves,  rather  than  from  the 
highly  developed  leaves  which  we  now  know.  Against  this,  we  have 
to  consider  that  those  floral  parts  were  probably  of  correspondingly 
simple  development,  and  that,  in  the  higher  plants  of  today,  they 
have  undergone  a  development  which  has  kept  i)ace  with  that  of  their 
leaves. 

As  to  what  constitutes  the  tyjjical  leaf,  we  are  confronted  by  two 
views.  Structurally  considered,  it  must  be  such  a  leaf  as  represented 
by  Fig.  467,  but  such  leaves,  as  we  now  see  them  upon  plants,  do  not 
apparently  so  well  perform  all  the  functions  of  the  leaf  as  those  which, 
like  Fig.  .'!,  have  developed  the  modern  leaf-parts. 

The  Leaf-Surfaces. — Very  rarely  has  the  leaf  a  terete  form  and  a 
radial  structure  as  seen  in  transverse  section.  Typically  it  is  a  flattened 
body.  One  flattened  surface,  the  Ventral,  faces  upw^ard  or  toward  the 
stem  which  bears  it,  and  is  ordinarily  spoken  of  as  the  upper  surface. 
The  under  or  outer  surface  is  technically  known  as  the  lower  or  Dorsal. 
By  a  partial  twist  in  the  petiole,  the  surfaces  may  become  laterally 


THE  STIITLKS  17:i 

placed,  tlu'  cduvs  vcrticjil.  In  ;i  IVw  leaves,  tlie  surfaces  are  normally 
in  the  latter  i)<)siti()n.  Between  the  (h)rsal  and  ventral  surfaces,  there 
are  usuall\-  (hll'erenees  sufficient  to  necessitate  their  description  sepa- 
rately. In  such  descrii)ti()ns,  it  is  better  to  speak  of  the  dorsal  surface 
as  being  underneath  rather  than  "helow,"  as  the  latter  term  may 
confuse  it  with  the  basal  region. 

Anatomical  Elements  of  the  Leaf. — It  has  been  shown  that  the  leaf 
originates  and  develops  as  an  extension  of  tlie  peril)lem,  covered  by 
that  of  the  dermatogen,  and  that  it  develo])s  a  stele  which  becomes 
continuous  with  that  of  the  stem.  In  other  words,  its  mode  of  develop- 
ment is  precisely  like  that  of  a  stem-branch.  We  have  in  it,  therefore, 
all  the  elements  which  characterize  primary  stem-structure.  The 
connection  of  the  leaf  with  the  stem  is  usually  by  a  s})ecially  arranged 
and  constructed  tissue,  forming  a  distinct  organ,  the  pulvinus,  which 
provides  an  articulation  designed  to  afford  a  prompt  and  ready  separa- 
tion of  the  leaf  at  the  conclusion  of  the  performance  of  its  function, 
as  well  as  for  certain  movements  and  changes  of  position  during  life. 

Just  as  branches  of  the  cauline  stele  pass  into  leaf  and  branch,  so 
do  those  from  the  foliar  stele  pass  laterally  into  its  expansions,  and 
secondary  and  tertiary  ones  successively  pass  from  them.  These 
branches  are  \ery  frequently  joined  at  their  distal  ends  to  others  (Fig. 
525,  o),  as  well  as  at  their  proximal  ends  to  the  parent  system.  Whether 
such  is  or  is  not  the  case,  the  result  of  the  branching  is  the  production 
of  a  framework  or  skeleton  which  forms  a  support  to  the  parenchymatous 
tissue  which  fills  its  meshes  and  co^•ers  its  surface,  the  latter  being  in 
turn  covered  by  the  epidermis. 

Except  as  to  the  general  characters  which  follow  under  leaf-classi- 
fication, it  is  im])ossible  to  ascertain  the  structure  of  the  cortex  and 
epidermis  of  the  leaf  by  ordinary  methods,  so  that  this  subject  is 
relegated  entirely  to  the  (lei)artment  of  histology. 

The  Stipules. — Before  ])roceeding  to  the  study  of  the  leaf-blade, 
which  specially  concerns  us,  certain  peculiarities  of  the  stipules,  and 
of  the  petiole,  may  be  considered.  The  original  function  of  the  stipules 
was  probably  to  afford  a  protective  covering  to  the  bud.  While  this 
function  still  persists,  it  is  doubtful  if  that  of  increasing  the  foliaceous 
surface  has  not  come  to  be  of  greater  importance.  We  should,  therefore, 
expect  them  to  develop  tissues  and  forms  resembling  those  of  the  leaf- 
blade,  and  such  is  the  case,  making  them  subject  to  the  same  classifica- 
tion and  terminology  in  those  directions  as  will  be  ai)plied  to  the  leaf- 
blade.     They  ha\'e,  however,  certain  peculiarities  of  their  own  which 


174 


THE  LEAF 


here  require  attention.  As  to  their  presence  or  absence,  leaves  which 
possess  them  are  called  Stipulate;  those  which  do  not,  Exstipulate: 
As  they  frequently  fall  with  the  expansion  of  the  bud,  there  is  great 
danger  that  a  stipulate  plant  may  be  mistaken  for  one  which  is  not. 

As  to  their  duration,  in  relation  to  the  leaf-bud  and  leaf,  the  terms 
caducous,  deciduous,  persistent,  and  so  on,  are  applied  to  them  as  to 
the  parts  of  the  perigone. 

It  has  been  shown  that  the  two  stipules  of  a  leaf  may  unite  with 
one  another  by  either  margin.  They  may  also  unite  with  either  the 
petiole  or  margin  of  the  leaf -blade,  or  with  the  stem  of  the  plant,  in  which 


Fig.  473.    Cordate   leaf   of   Nymphaca,  with   the   margins   of   the  sinus  connate  at   a.      474.    Inter- 
petiolar  stipules  of  Diodia.    475.  Stipulate  compound  leaf,  with  stipellate  leaflets. 


cases  they  are  called  Adnate.  When  leaves  are  opposite  one  another, 
the  two  stipules  between  them  may  unite  with  one  another  by  their 
adjacent  margins,  forming  the  Interpetiolar  Stipule  (Fig.  474,  a). 
Especial  importance  attaches  to  this  class  of  stipules,  because  of  the 
remarkable  variation  displayed  in  their  subdivision  and  appendaging, 
and  the  great  value  of  their  characters  in  generic  classification  in  certain 
families,  especially  in  that  highly  medicinal  one,  the  Rubiaceae. 

In  some  cases,  the  stipules  so  closely  resemble  the  foliage-leaves 
that,  together  with  the  blade,  they  present  the  appearance  of  a  group 
of  three  leaves  standing  side  by  side.  In  the  case  of  opposite  leaves, 
this  sometimes  makes  an  apparent  whorl  of  six  similar  leaves,  or, 


DURATIOS   AM)   RI'JTKNTION    UPOX    TIIK   I'LAST  175 

tlirouiili  the  union  of  the  adjacent  stipules,  of  four.  In  sncli  cases,  the 
k'a\cs  \vhich  are  sti])ulcs  can  be  distinguished  from  the  others  by  their 
faihu-o  to  develop  axiHary  buds.  The  stipule  is  frequently  transformed 
into  one  or  more  bristles,  or  even  strong  spines,  and  occasionally  into 
a  tendril  (Fig.  o()r)). 

A  secondary  stipule,  borne  at  the  base  of  one  of  the  (li\isions  of  a 
compound  leaf,  is  called  a  StipeUa  (Fig.  475,  a). 

The  Petiole. — Leaves  possessing  the  Petiole;  are  called  I'etioled  those 
wanting  it  are  called  Sessile  (Fig.  478).  Occasionally  the  petiole  is 
present,  but  adnate  to  the  stem  of  the  plant,  thus  appearing  wanting. 
In  other  cases,  while  quite  free  from  the  plant-stem,  more  or  less  of 
the  base  of  the  petiole  will  clasp  it.  Such  a  Clasping  petiole  must  not 
be  mistaken  for  a  leaf-sheath,  which,  as  we  have  seen,  is  not  a  true 
petiole  at  all,  but  the  development  of  a  different  part  of  the  primary 
leaf. 

When  the  margins  of  the  petiole  throughout  are  herbaceous  and  in 
continuation  with  the  blade,  the  petiole  is  said  to  be  INIargined  or 
Winged. 

When  the  margins  of  the  ])etiole  are  less  ])r()n()unced,  ])ut  yet  present 
anfl  elevated,  so  as  to  form  a  groove  upon  its  upper  siu'face,  the  petiole 
is  called  Channelled. 

Other  characters  of  the  petiole,  such  as  its  triangular  or  semicircular 
form  in  transverse  section,  its  relati\-e  stoutness,  and  the  character  of 
its  surface,  need  not  be  specially  considered.  Certain  special  modifica- 
tions in  the  function  of  the  petiole  will  be  considered  under  modified 
leaves. 

The  attachment  of  the  i)eti()le  to  the  leaf-blade  is  always  really 
marginal,  though  by  the  cohesion  of  liasal  lobes  (Fig.  47i),  a)  it  is  often 
apparently  intra-marginal  or  even  central.  Basal  lobes  may,  ui)on  the 
other  hand,  be  adnate  along  the  petiole,  or  the  same  appearance  may 
be  produced  })y  the  gradual  difi'erentiation  of  petiole  into  blade. 

Petiolar  Glands. — (ilands  of  various  forms  often  appear  upon  some 
part  of  the  jx'tiole,  and  their  appearance  is  characteristic  and  of  diag- 
nostic value,  as  in  distinguishing  the  species  of  Pnniu.s  and  Cassid. 

Duration  and  Retention  upon  the  Plant. — As  the  duration  of  the  leaf 
and  its  retention  upon  the  i)lant  ha\e  to  do  in  part  with  the  nature  of 
the  petiole,  it  may  be  here  considered.  Lca\es  are  Annual,  and  the 
])lants  producing  them  deciduous,  when  their  duration  is  tluough  a 
single  season  only,  and  Fvergreen,  when  they  remain  in  their  normal 
and  active  condition  into  the  succeeding  season.     Evergreen  leaves 


176 


THE  LEAF 


may  be  either  biennial,  the  onHnary  form,  or  perenniah  Persistent 
leaves  are  those  which  remain  upon  the  tree,  but  in  a  dead  condition, 
being  usually  forced  off  by  the  growth  of  the  following  season. 

The  Lamina. — Coming  now  to  the  consideration  of  the  leaf-blade,  we 
note  that  it  is  to  be  studied,  and  its  varieties  classified,  with  regard  to 
its  relation  to  its  support,  its  texture,  surface,  form — this  including  the 
general  outline  as  well  as  special  forms  of  apex  and  base — venation, 
margin,  division,  and  modification  of  form  and  function. 

Relation  of  the  Leaf-base  to  the  Plant-stem. — When  a  i)etiole  or  a 
lamina  has  grown  fast  for  a  portion  of  its  length  to  the  plant  stem,  it  is 
called  Adnate  (Fig.  477).  One  whose  base  is  heart-shaped  and  surrounds 
the  plant  stem,  whether  growing  fast  to  it  or  not,  is  called  Amplexicaul 


47Z 


Modifications  of  the  leaf-base:  Fig.  476.  Connate-perfoliate  (boneset).  477.  Adnate  to  plant  stem 
{V erhascum) .  478.  Sessile  (Solidago).  479.  Amplexicaul  (^Asler  Novae-Angliae).  480.  Perfoliate 
{Oakesia).     481.   Margined  {PlaiUago).     482.  Continuous.     483.  Intramarginal-peltate. 


or  Clasping  (Fig.  479).  When  the  basal  lobes  of  a  clasping  leaf  entirely 
surround  the  stem  and  become  connate  upon  the  other  side,  so  that  the 
Stem  appears  to  be  growing  up  through  a  perforation  in  the  leaf,  the 
leaf  is  called  Perfoliate  (Fig.  480).  When  opposite  leaves  are  connate 
by  their  bases  they  are  called  Connate  or  Connate-perfoliate  (Fig,  476). 
When  the  bases  of  sheathing  leaves  clasp  the  stem  in  such  a  manner  as 
to  present  a  V-shape  in  transverse  section,  and  one  is  superposed  upon 
another  in  the  same  manner,  they  are  called  Equitant. 

Relation  of  the  Base  to  the  Petiole. — As  to  the  attachment  of  the  blade 
to  the  petiole,  the  leaf  is  Peltate  when  this  insertion  is  intra-marginal 
through  the  connation  of  the  edges  of  basal  lobes.  A  peltate  leaf  may 
be  Centrally  (Fig.  473),  or  Eccentrically  (Fig.  483)  peltate.  When  the 
petiole  changes  so  gradually  into  the  lamina  that  it  is  impossible  to 


SURFACE  177 

say  wliere  one  Ix^^ins  aiul  the  other  cinls,  we  say  they  arc  Continuous 

(Fis-  4S2)- 

Texture. — As  to  their  texture  and  consistency',  the  or(Hnai-y  form  of 
leaf,  in  which  it  ])ossesses  active  chlorophyll  tissue,  is  denominated 
Ilerhaceous,  in  contradistinction  to  the  Scarious  or  Scariose  form,  in 
which  it  has  a  (hy  and  papery  texture.  Herbaceous  leaves  are  ]\Iem- 
l)ranacet)us  in  their  ordinary  form,  that  is,  not  excessively  thickened, 
Coriaceous  when  tough  and  leathery.  Fleshy  or  Succulent  when  largely 
parenchymatous,  thickened,  and  juicy.  A  leaf  which  exhibits  trans- 
lucent dots  when  held  against  a  strong  light,  due  to  the  presence  of 
oil-glands,  is  called  Pellucid-punctate. 

Surface. — The  surfaces  of  leaves  may  be  classified  in  two  ways:  First, 
as  to  the  characteristics  of  the  individual  trichomes  which  they  bear; 
second,  as  to  the  general  surface  effects  (Indumentum)  which  result  from 
the  latter.  The  former  method,  although  it  cainiot  be  taken  uj)  in  this 
part  of  the  work,  is  of  very  great  importance  in  the  characterization 
of  medicinal  herbs  and  leaves,  especially  as  it  constitutes  one  of  the 
greatest  aids  to  the  identification  of  powders.  The  latter  method  can 
only  be  studied  with  advantage  by  the  actual  examination  of  typical 
specimens,  it  being  almost  impossible  to  characterize  the  different  forms 
by  definition.  A  surface  is  Opaque  when  it  is  not  shining  or  lustrous. 
It  is  Glabrous  when  it  does  not  possess  any  trichomes  in  such  forms  as 
to  detract  from  the  smoothness  of  the  surface.  It  is  Glaucous  when 
covered  with  a  waxy  exudation,  imparting  to  it  a  peculiar  whitish 
appearance  ("bloom"),  such  as  characterizes  the  surface  of  an  ordinary 
black  grape.  It  is  Scurfy  when  covered  with  more  or  less  of  an  indumen- 
tum in  the  form  of  granular  or  detached  scaly  masses.  When  the  matter 
of  such  masses  is  more  thinly  distributed,  appearing  in  the  form  of  a 
powder  rather  than  a  scurf,  the  surface  is  called  Pulverulent. 

A  Pubescent  surface  is  a  hairy  surface  which  is  not  readily  dis- 
tinguished as  pertaining  to  any  one  of  the  other  specific  classes. 

If  the  hairs  of  a  ])ubescent  surface  are  very  short  and  fine,  so  that 
the  consequent  roughness  is  reduced  to  a  minimum,  the  surface  is 
called  Puberulent. 

If  a  hairy  indumentum  is  fine  and  of  an  ashy-gray  color,  the  hairs  not 
arranged  in  any  regular  direction,  the  surface  is  Cinereous. 

If  the  hairs  all  lie  in  one  direction,  are  closely  appressed,  and  ha\e  a 
shiny  or  silky  luster,  the  surface  is  called  Sericeous. 

If  this  luster  is  intensified  and  of  a  strongly  whitish  color,  whether 
the  trichomes  be  hairs  or  scales,  the  surface  is  denominated  Argentcous. 
12 


178  THE  LEAF 

Such  hairs  as  are  cai)able  of  producing  a  sericeous  surface  are  them- 
selves denominated  sericeous  or  silky,  even  though  they  be  in  insuffi- 
cient numbers  to  impart  this  character  to  the  general  surface. 

A  surface  tending  toward  the  sericeous,  but  not  sufficiently  pro- 
nounced, is  called  Canescent. 

When  there  is  a  dense  covering  of  more  or  less  elongated  and  matted 
hairs,  the  surface  is  called  Tomentose. 

When  such  a  covering  is  thin,  its  hairs  less  elongated,  it  is  called 
Tomentellate. 

Whene  there  is  a  covering  of  thinly  distributed,  elongated,  moder- 
ately soft  hairs,  which  are  not  closely  appressed,  the  surface  is  Pilose. 

When  hairs  are  similarly  distributed,  but  are  elongated  and  coarse, 
the  surface  is  Hirsute. 

When  similar  coarse  hairs  are  rather  stiff,  lie  in  one  direction,  some- 
what appressed,  and  particularly  when  each  develops  from  an  elevated 
base,  the  surface  is  Strigose. 

A  surface  which  possesses  an  indumentum  of  scales  is  called  Lepidote. 

A  surface  is  called  Papillose  when  it  is  minutely  warty,  or  tuberculate, 
due  usually  to  glands  underneath  the  siu-face. 

Wlien  the  indumentum  consists  of  hard,  ele^'ated  points,  giving  a 
roughness  to  the  surface,  the  latter  is  Scabrous. 

When  such  elevations  are  more  pronounced,  unyielding,  and  sharp- 
pointed,  the  surface  is  Hispid. 

A  surface  which  is  roughened  by  the  presence  of  numerous,  closely- 
set  wrinkles  is  Rugose. 

When  a  surface  is  made  up  of  small,  blister-like  elevations  consisting 
of  the  arching  interspaces  between  the  veins,  it  is  Bullate  (Fig.  484). 
The  opposite  surface,  containing  the  cavities  of  the  bullae,  is  called 
Cancellate  (Fig.  485). 

When  the  hairy  covering  is  chiefly  confined  to  the  margin,  presenting 
itself  in  the  form  of  a  fringe  of  hairs,  the  term  Ciliate  is  applied  (Fig. 
475). 

A  surface  which  is  marked  by  spots  differing  in  color  from  the  remain- 
der of  the  surface  is  called  Maculate.  If  spots  of  any  kind  be  small 
and  dot-like,  the  term  Punctate  is  applied. 

Finally,  it  is  to  be  noted  whether  the  veins  or  ribs,  and  if  so  which 
of  them,  are  prominent  upon  both  sides  or  either  side,  or  whether,  upon 
the  contrary,  they  are  depressed  (called  Impressed)  below  the  general 
surface.  At  times  a  rib  or  vein  will  not  be  impressed,  but  will  yet  be 
Channelled,  and  may  appear  impressed  upon  casual  observation. 


SURFACE. 


179 


By  the  outliiu'  of  tlic  leaf,  we  refer  to  the  general  form  of  its  margin, 
wliether  that  he  I'litire,  or  not.  If  not,  then  the  j^eneral  form  of  an 
outHne  is  determined  by  connecting'  the  extreme  points  of  its  margin 
with  one  another  (Fig.  480,  an  ohovate  onthne).  It  matters  not,  there- 
fore, whether  a  leaf  be  entire,  toothed,  h)bed,  or  ])arted,  or  even  if  it  be 
entirely  compoimd  or  decompound,  its  outline  will  l>e  the  same,  pro- 
vided a  line  connecting  its  extreme  marginal  points  with  one  another 
possess  a  given  form.  The  forms  of  leaves  on  this  basis  may  be  divided 
into  three  general  classes — (a)  those  broadest  at  or  about  the  middle, 
(6)  those  broadest  at  some  ])oint  al)ove  the  middle,  (c)  those  broadest 
at  some  \nnnt  below  the  middle. 


Vc?^ 


fz% 


'*>« 


Fig.  4S4.  A  bullate  upiicr  8urf;i( 


,   A  caiu'olla 


^ 


Of  the  first  class,  beginning  with  the  narrowest,  \\e  have  the  Capillary 
or  I  lair-like  forms,  the  P^iliform  or  Thread-shaped  (Fig.  491),  the  Acerose 
or  Needle-shaped  (Fig.  492),  as  those  of  the  pine,  and  the  Linear  or 
Ribbon-shaped  (Fig.  487),  all  of  which  are  so  elongated  that  they 
present  the  appearance  of  being  about  of  uniform  width  throughout. 

A  leaf  similar  to  but  shorter  than  the  linear,  in  proportion  to  its 
breadth,  without  regard  to  the  character  of  its  apex  or  base,  is  Oblong 
(Fig.  488). 

One  of  similar  form,  but  Inning  a  length  of  not  more  than  t^\i(•e  or 
thrice  its  breadth,  and  narrower  than  a  circle,  is  ()\al  (Figs.  489  and 
490),  a  term  which  must  not  be  confoniuied  with  Ovate. 

If  an  oblong  or  an  oval  leaf  i)ossess  a  regularly  rounded  outline  into 
and  through  the  ai)ical  and  basal  portions,  it  is  called  Elliptical.  \Ve 
have,  therefore,  two  forms  of  the  elliptical  leaf,  denominated  respectively 
Oblong-Ellii)tical  (Fig.  488)  and  ()val-Ellii)tical  (Fig.  489). 


180 


THE  LEAF 


A  circular  leaf  (Fig.  493)  is  called  Rotund  or  Orbicular. 

Finally,  we  have  the  leaf  which  is  broader  than  circular — that  is,  its 
lateral  diameter  is  greater  than  its  vertical,  and  this  is  called  Trans- 
versely Elliptical. 


497 


Leaf  outlines:  Fig.  486.  Obovate  compound  leaf  of  rose.  478.  Linear  leaf  of  I/ireon'a.  488.  Oblong- 
elliptical  {Poterium).  489.  Oval  elliptical  {Pyrola).  490.  Imperfectly  oval  {Prunus).  491.  Filiform 
(Drosera).  492.  Acerose  (Pinus).  493.  Rotund  (Pyrola).  494.  Ovate  {ColUnsonia).  495.  Reniform 
(Asarum).     496.  Lanceolate  {Solidago).     497.  Lancelinear  (Salix). 


Forms  Broadest  below  the  Middle.— Those  which  are  broadest  at  some 
point  below  the  middle  or  above  the  middle  should,  in  description, 
besides  being  designated  by  the  class-name  of  their  form,  have  it 
specified  in  some  way  as  to  about  the  portion  at  which  the  greatest 
breadth  occurs. 

Beginning  with  the  broadest  ones,  we  have  that  which  is  broader  than 
long  and  with  a  heart-shaped  base,  called  Reniform  (Fig.  495). 

One  which  possesses  a  length  greater,  but  not  more  than  two  or  three 
times  its  breadth,  is  called  Ovate  (Fig.  494). 

One  of  similar  form,  but  its  comparative  length  greater,  is  called 


FORMS  niiOADEST  ABOVE   THE  MIDDLE 


ISl 


Lanceolate  (Fig.  496).  One  wliich  is  ovate,  but  with  the  greatest 
l)rea(ltli  at  the  very  base,  the  margins  not  or  ])ut  httle  curved,  so  that 
it  is  approximately  triangular,  is  called  ])clt()i(l  (Fig.  498). 

One  still  narrower,  but  of  similar  form,  Ijcaring  the  same  relation  to 
the  lance()l;it(>  wliich  the  deltoid  does  to  the  ovate,  is  called  Subulate, 
or  awl-shai)ed  (Fig.  499). 

An  ovate  or  oval  leaf  whose  outline,  instead  of  being  regularly  curxed, 
is  made  uj)  of  four  comi)aratively  straight  hues  is  called  Traj)e/.oidal  or 
Angularly-ovate.  Another  term  which  is  appHed  to  it  is  Khomboidal 
(Fig.  :)()()). 


Leaf  outlines:  Fig.  498.  Deltoid  {Betula).  499.  Subulate  (diagrammatical).  500.  Rhomboidal 
{Chekan).  501.  Obovate  (Lindera).  502.  Oblanceolate  {SoHdago).  503.  Spatulate  (Antennaria). 
504.  Talcsitc  (Eucalyptus).    505.   Inaequilatcral  (//amamcZis). 


Forms  Broadest  above  the  Middle. — ]\Iost  of  the  forms  just  referred  to 
are  i)aralleled  by  exactly  similar  forms  in  which  the  widest  portion  is 
above  the  middle.  The  names  for  these  are  formed  by  ])refixing  the 
syllable  oh  to  the  corresponding  names  of  the  other  forms;  as,  Obovate 
(Fig.  501),  Oblanceolate  (Fig.  502). 

When  an. Obovate  or  Oblanceolate  leaf  possesses  a  broad,  rounded 
ai)ex,  and  a  somewhat  elongated  lower  portion,  it  is  called  Spatulate 
(Fig.  50;^). 

The  outline  of  a  leaf  is  greatly  modified  when  the  jxtrtioii  U])on  one 
side  of  the  midrib  is  longer  or  broader  than  that  upon  the  other,  giving 
us  Inequilateral,  I'nequal,  or  Oblique  forms  (Fig.  505). 


182 


THE  LEAF 


Wlien  such  a  leaf  has  its  midril)  laterally  (•iir\(>(l,  it  is  styled  Falcate 
or  sword-shaped  (Fig.  504). 

Modifications  of  this  as  regards  the  comparative  length  and  breadth 
of  the  leaf  are  Sickle-shaped  and  Scimeter-shaped. 

Forms  of  the  Apex. — A  large  numl)er  of  terms  are  employed  to  indicate 
especially  the  form  of  the  apex  of  the  leaf. 


si;e. 


SI3. 


J/4. 


S/X 


Forma  of  apex:  Fig.  506.  Obcordate  (OxaZis).  507.  Notched  (Linoiieredrore).  508.  Abruptly  acumi- 
nate and  acute  {Ailanlhus).  509.  Emarginate  (Pilocarpus).  510.  Acute  (Lonicera).  511.  Abruptly 
pointed  (Ulmus).  512.  Retuse.  513.  Abruptly  acuminate  and  obtuse  (Fraxinus).  514.  Tapering 
{Panicum).     515.  Blunt  (Plantago). 


Beginning  with  one  which  is  inversely  cordate — that  is,  with  the 
sinus  at  the  Apex — we  have  the  Obcordate  form  (Fig.  506).  When  the 
sinus  is  smaller,  it  is  called  Emarginate  (Fig.  509),  and  when  very  slight, 
Retuse  (Fig.  512).  If  the  sinus  be  an  angular  one  with  straight  sides, 
it  is  called  Notched  (Fig.  507).  If  the  apex  be  abrui)tly' terminated, 
as  though  cut  across  in  a  straight  line,  it  is  called  Truncate.  If  any 
portion  of  the  apex  of  the  leaf  be  narrowed  into  a  point,  the  leaf  is 
called  Pointed  (Fig.  511,  etc).  If  such  narrowing  be  gradual,  so  that  the 
point  is  considerably  longer  than  broad,  it  is  called  Acuminate.    If  the 


FnR^fs  OF  riiE  base 


1S3 


ac'umiiiation  is  preceded  hy  an  abrupt  eoiitractioii,  it  is  distiii<,Miislied  as 
beiiiji:  AI)riiptly  Aeuininate  (Figs.  511  and  o\'.'}). 

If  the  narrowing  be  very  gradual  and  not  jjreeeded  by  an  abrupt 
eontraetion,  the  ajjex  is  said  to  be  Tapering  (Fig.  514);  if  still  more 
drawn  out,  Attenuate.  If  the  point  of  the  leaf  be  extremely  abrupt 
and  very  small,  it  is  Mueronate  when  soft  and  herbaceous,  Cuspidate 
when  hard  and  stift',  like  a  tooth. 


Fig.  51G.  Dioilalia  leaf,  with  produced  base,  rounded  apex,  reticulate  venation.  517.  Apiculatc 
apex.  518.  Cuneate  base  (white-oak).  519.  Cordate  and  produced  base  (violet).  520.  Sagittate 
base  Wolygonum).  521.  Aurioulate  base  (Aster).  522.  Hastate  base  {Rutnex),  523.  Oblique  base 
(Datura). 

Any  of  the  above-mentioned  forms  may  be  either  Acute,  when  the 
ultimate  apex  is  sharp  (Figs.  508,  510,  and  514),  Obtuse  when  not  so 
(Figs.  511  and  513),  Blunt  when  very  obtuse  (Fig.  515),  or  even  Hounded 
(Fig.  51(;). 

x\  leaf  which  has  the  midrib  only  extended  into  a  bristle-shajjed 
point  is  called  Apiculate  (Fig.  517),  and  this  condition  can  apply  to  a 
cordate  as  well  as  to  other  forms  of  the  apex. 

Forms  of  the  Base.— The  special  forms  of  the  base  of  the  lcaf-i)la(le 
yiehl  a  correspondingly  large  number  of*  terms.  Tlu>  terms  cordate, 
truncate,    rounded,    blunt,    obtuse,   acute,    acuminate,   and    abruptly 


184  THE  LEAF 

acuminate,  require  no  definitions  in  addition  to  those  which  have  been 
apphed  to  simihir  forms  of  the  apex. 

When  the  two  sides  of  the  base  are  straight,  and  come  to  an  acute 
point,  it  is  called  Cuneate  or  Wedge-shaped  (Fig.  518). 

A  base  the  form  of  which  yields  later  to  a  sudden  downward  ])rolonga- 
tion  or  acumination  is  called  Produced  (Figs.  516  and  519). 

In  all  forms  of  the  cordate  base  the  greatest  care  must  be  taken  to 
specify  the  precise  character  both  of  the  sinus  and  of  the  lobes.  The 
former  must  have  its  form  or  outline  specified,  as  well  as  the  angle 
which  it  makes.  It  should,  moreover,  be  carefully  noted  whether  the 
leaf-base  at  the  summit  of  the  petiole  be  produced  into  the  sinus,  in 
which  case  it  is  called  Intruded  (Fig.  519).  Sometimes  the  lobes  of  a 
cordate  base  will  meet  one  another,  or  even  overlap. 

The  forms  of  the  lobes  are  also  capable  of  taking  descriptive  titles 
similar  to  those  characterizing  the  lamina  in  general.  The  principal 
of  such  terms  are  Auriculate,  when  the  lobes  are  rounded  similarly 
to  the  lobe  of  the  human  ear  (Fig.  521) ;  Sagittate,  when  pointing  down- 
ward, and  acute,  like  the  lobes  of  an  arrow  head  (Fig.  520) ;  Hastate  or 
Halberd-shaped,  when  turned  outward  (Fig.  522). 

A  base  is  Oblique  or  Inequilateral  when  descending  lower  upon  one 
side  than  upon  the  other  (Figs.  521  and  523). 

Venation  or  Nervature. — Bundles  which  obviously  separate  from  one 
another  at  or  near  or  below  the  base  of  the  blade,  and  maintain  their 
course  well  toward  the  apex  or  margin,  are  called  Costae  or  Ribs  if 
equally  prominent  (Fig.  527),  nerves  if  lateral  and  markedly  less  promi- 
nent than  one  or  more  of  the  central  ones  (Fig.  529). 

The  central  one,  whether  there  be  others  or  not,  is  the  Primary  or 
Midrib  (Fig.  524,  a).  Branches  or  ribs  or  nerves  are  called  A'eins,  and 
they  are  distinguished  as  Secondaries  (6)  when  departing  from  the  mid- 
rib, Tertiaries  (c)  when  departing  from  Secondaries,  and  so  on.  In 
palmately  veined  leaves,  the  central  is  called  the  IMiddle  Primary,  the 
other,  the  Lateral  Primaries.  The  middle  one  is  here  also  called  the 
midrib,  if  distinctly  stronger  than  the  others.  Secondaries  of  lateral 
ribs  or  nerves  must  be  especially  so  designated  in  description.  Very 
small  veins  are  called  Veinlets. 

The  greatest  importance  in  descriptive  terminology  pertains  to  the 
classification  of  leaf-\'enation,  owing  to  the  frequency  with  which  leaves 
must  be  identified  in  such  a  fragmentary  state  that  there  is  little  beyond 
the  surface  and  venation,  with  possibly  a  portion  of  the  margin,  to 
assist  us. 


VENATION  OR  NERVATURE 


185 


The  forms  all  fall  within  two  principal  classes,  which,  in  general, 
characterize  respectively  the  monocotyledons  and  the  dicotyledons. 
The  former  hears  its  ])rincipal  veins  more  or  less  ])arallel  with  one 
another,  and  these  are  munerons.  Snch  lea\es  are  called  I'andlcl- 
veined  (Fig.  52G). 


Venation  or  Ncrvature:  Fig.  524.  Pinnateiy  veined  leaf  of  Castanea:  a,  midrib;  b,  secondaries;  c, 
tertiaries.  525.  Reticulate  leaflet  of  Pilocarpus:  a,  anastomosis  of  secondaries.  526.  Parallel-veined 
leaf  of  Convallaria.  527.  Flabellately  costate  leaf  of  Plantago.  528.  Digitately  veined  leaf  of  Cercis. 
529.  Costinerved  leaf. 

In  the  second  form  there  is  hut  one,  or  a  comparati\'ely  few  t)ri<,nnal 
veins,  and  these  give  rise  to  successively  developed  branch  systems, 
the  whole  forming  a  network  or  Reticulum.  Such  leaves  are  called 
reticulated  or  Xetted-veined  (Fig.  524,  etc.).  These  veins  may  or  may 
not  anastomose  or  intercommunicate  at  their  distal  ends.    When  they 


186  THE  LEAF 

do,  the  term  Reticulate  is  applied  to  them  in  a  special  or  restricted 
sense  (Fig.  525).  In  leaves  of  the  last-named  class  the  details  of  the 
method  of  intercommunicating  are  very  important.  Thus,  in  some  cases, 
the  end  of  each  secondary  is  arched  upward  into  the  secondary  next 
above  (Fig.  525).  In  such  case  it  is  important  to  note  the  comparative 
distance  from  the  margin  at  which  the  communication  takes  place  and 
the  angle  at  which  the  two  meet,  as  these  characters  are  always  constant 
in  the  same  species.  In  other  cases  the  secondaries  (or  the  ribs,  as  in 
Fig.  568)  are  directly  connected  by  straight  and  parallel  secondaries 
or  tertiaries,  or  in  still  others  (Fig.  516)  by  an  irregular  intervening 
network  of  small  veins.  Secondaries  connected  by  the  first  method 
are  usually  also  connected  near  the  base  with  the  midrib  by  a  number 
of  curved  tertiaries. 

When  the  principal  veins  or  nerves  of  a  leaf  are  straight,  it  is  called 
Rectinerved;  when  curved,  Curvinerved.  The  latter  term  refers  to  a 
regular  and  characteristic  curve,  not  to  a  crooked  course.  Some  leaves 
are  characterized  by  possessing  waving  or  crooked  nerves  or  veins. 

Two  great  classes  of  netted-veined  leaves  are  recognized,  the  one  in 
which  there  is  a  main  Rachis  or  midrib,  from  which  secondaries 
extend  regularly  toward  the  margin.  This  form  is  knowp  as  the  Penni- 
nerved  or  Pinnately  veined  leaf  (Fig.  524),  The  number  of  pairs  of 
secondaries,  whether  they  originate  exactly  opposite  to  each  other  or 
somewhat  irregularly,  is  within  fair  limits  characteristic  of  the  species, 
and  should  be  stated.  The  same  is  true  of  the  angle  at  which  they 
radiate  from  the  midrib.  In  the  case  of  additional  ribs  or  nerves  of 
such  a  leaf,  their  number  and  stoutness  as  compared^with  the  midrib, 
their  comparative  length  and  the  position  which  they  take  in  the  leaf 
are  all  important.  The  second  great  class  of  netted-veined  leaves  is 
that  in  which  a  number  of  approximately  equal  ribs  ra^aliate  from  the 
basal  region.  Such  leaves  are  known  as  Palmately>or  Digitately 
Veined  (Figs.  527  and  528).  There  are,  of  course,  many  forms  of  inter- 
grading  (Figs.  529  and  568)  between  such  leaves  and  pinnately  veined 
leaves  with  secondary  ribs  or  nerves.  Sometimes  the  nerves  start  from 
the  very  base  of  the  leaf,  in  which  it  is  called  Basinerved  (Fig.  528) ; 
at  others  from  the  lower  portion  of  the  midrib,  when  it  is  called  Costi- 
nerved  (Fig.  529).  When  the  ribs  or  nerves  are  manifestly  continued 
downward  into  the  petiole,  the  leaf  is  called  Flabellately  nerved  (Fig. 
527). 

The  Leaf-margin. — The  manner  in  which  the  leaf-margin  comes  to 
deviate  from  an  entire  condition  has  already  been  indicated.     Three 


THE  J.KAF  MAIiCIN 


187 


special  forms  of  tootliiiii;-  arc  i-cconni/cd,  in  accordance  with  llic  form 
and  direction  of  the  teetli.  When  the  hitter  jx.int  in  an  outward  direc- 
tion the  margin  is  caUed  Dentate  (Fiji;.  ")."54);  wlieii  toward  the  ai)ex  of 
the  leaf,  Serrate  (Fig.  I'^'.V^).  When,  instead  of  l)einij;  pointed,  the  teeth 
are  rounded,  the  margin  is  Crenate  (Fig.  530). 


Margins:  Fig.  530.  Crenate  {Daliharda) .  531.  Doubly  serrate,  the  teeth  appressed  (Ulmus).  532. 
Obsoletely  serrate  (.Gaultheria) .  533.  Serrate.  534.  Dentate  (Viburnum).  535.  Serrulate  (Vibur- 
num).    530.   Ropand  (Hamnmclis).     537.  Sinuate. 


Diminutives  of  these  terms,  indicating  that  the  teeth  are  very  small, 
are  Denticulate,  Serrulate  (Fig.  535),  and  Cremilate.  To  any  of  these 
terms  tiie  word  "Minutely"  may  be  prefixed  as  indicating  that  the 
teeth  are  still  smaller.  Of  each  of  these  three  ])riiici])al  forms  there 
are  a  number  of  sub-forms. 

When  the  teeth  bear  smaller  or  secondary  teeth,  the  word  "  Doubly" 
is  prefixed  (Fig.  531,  (l()ubl>-  serrate). 

When  serrate  teeth  ha\-e  their  ])()ints  \-ery  stronglx'  directed  toward 
the  apex  or  ai)pearing  as  though  pressed  inward  against  the  margin, 
they  are  called  .Xpprcssed  (Fig.  o.n ,  partly).  They  may  even  be 
Incurved.  When,  ui)on  the  other  hand,  the  ends  of  the  teeth  are  turned 
outward,  they  arc  called  Salient.    When  the  points  of  the  teeth  are  very 


188 


THE  LEAP 


fine  and  })ro(luced  in  tlie  form  of  bristles  they  are  called  Spinulose  (Fig. 
524). 

When  a  margin  shows  indications  of  being  dentate,  serrate,  or  crenate, 
but  the  teeth  are  not  distinctly  pronounced,  the  adjective  Obscurely 
is  prefixed.  For  this  word  that  of  "Obsoletely"  is  substituted  when 
the  leaf  possesses  a  relationship  such  as  to  make  it  probable  that  its 
ancestral  forms  were  more  strongly  characterized  by  this  condition 
(Fig.  532). 


Fig.  538.  Pinnatifid  (Pedicularis) .  539.  Palmatifid  (gooseberry).  540.  Laciniately  divided  (but- 
tercup). 641.  Slightly  revolute.  542.  Strongly  revolute  (i?o.sOTari>ius).  543.  Lobed,  the  lobes  acute, 
the  sinuses  obtuse  (_Quercus).  544.  Both  lobes  and  sinuses  obtuse  {Sassafras).  545.  Lobes  obtuse, 
sinuses  acute  (.Hepatica).     546.  Incisely  parted  (Geranium). 


When  the  teeth  and  their  sinuses  are  all  connected  in  such  a  way 
that  the  margin  represents  a  wavy  line,  the  latter  is  called  Hepand  or 
Undulate,  or  Sinuate  (Figs.  536  and  537).  When  a  leaf  is  so  deeply 
toothed  that  the  sinuses  reach  well  toward  the  middle  portion  (Figs. 
543  to  545)  the  term  Lobed  is  substituted  for  those  above  defined. 

When  the  division,  by  a  sharp  sinus,  extends  more  than  half-way  to 
the  middle,  yet  not  very  near  to  the  midrib,  it  is  called  Cleft  (Fig.  539). 

When  reaching  almost  to  the  midrib  (Fig.  538)  or  to  the  base  in  case 
of  a  digitate  leaf  (Fig.  546),  it  is  called  Parted,  and  when  all  the  way, 
Divided  (Figs.  540  and  559).  The  divided  leaf  is,  however,  not  the  same 
as  the  compound  leaf,  inasmuch  as  the  separation  of  its  blade  into 
distinct  leaflets  is  not  complete.    (Compare  Figs.  547  and  555.) 

The  cleft,  parted  or  divided  leaf,  is  either  Pinnatifid  (Figs.  538,  556, 


THE  COMPOUND  LEAF  189 

etc.)  or  Paliiiatifid  ( Fii^s.  540  and  540),  accor(lin,ti;  to  tlic  cliaractcr  of  Its 
venation.  In  all  forms  of  lobed,  cleft,  parted  or  <li\idc(i  leaves,  it  is 
necessary  that  the  detailed  characters  of  the  lohes  and  of  the  siinises 
should  be  specified.  The  lobe  may  be  acute,  while  the  sinus  is  rounded 
(Fig.  543),  or  the  reverse  may  be  true  (Fig.  545),  or  both  may  l)e  acute 
or  both  obtuse  (Fig.  548).  The  sinuses  as  well  as'  the  lobes  frequently 
possess  definite  and  characteristic  outhnes,  indicated  by  terms  such 
as  have  already  been  defined  in  connection  with  the  leaf.  When  the 
teeth  and  sinuses  are  outUned  by  straight  hues  and  sharp  terminations, 
as  though  notched  out  by  a  pair  of  scissors,  the  margin  is  said  to  l)e 
Incised  (Figs.  540  and  546).  When  the  divisions  and  sinuses  are  long 
and  narrow  in  addition  to  being  incised,  it  is  called  Laciniate  (Fig.  540). 
When  the  margin  of  a  leaf  is  turned  downward  or  backward  or  rolled 
backward,  it  is  said  to  be  Revolute.  Ordinarily  the  revolution  is  very 
slight  (Fig.  541),  but  occasionally,  particularly  upon  drying,  it  will  be 
found  extreme,  each  half  of  the  leaf  forming  a  roll,  the  two  meeting 
back  of  the  midrib  (Fig.  542). 

Before  proceeding  to  speak  of  the  forms  of  compound  leaves,  it 
should  be  stated  that  when  one  of  the  terms  above  defined  (and  the 
same  is  generally  true  of  descriptive  terms  used  in  other  parts  of  the 
work)  terminates  in  the  ending  ate  or  oid,  it  sometimes  indicates  that 
the  condition  tends  toward  but  does  not  quite  reach  that  named  by 
the  term  to  which  the  ending  is  appended.  For  example,  triangulate 
means  inclining  toward  triangular.  The  student  will  also  note  that 
between  nearly  all  the  forms  of  leaves  and  the  characters  indicated  by 
the  terms  above  defined,  there  are  intermediate  forms  connecting  them 
with  others. 

Inasmuch  as  it  is  necessary  in  description  for  such  forms  to  be 
indicated,  the  method  is  resorted  to  of  employing  the  two  terms  con- 
nected by  a  hyphen.  Thus,  Lance-ovate,  or  Ovate-lanceolate  (Fig. 
497)  indicates  that  the  form  is  intermediate  between  lanceolate  and 
ovate;  crenate-flentate  and  serrate-dentate  are  similar  illustrations. 

A  similar  intermediate  condition  is  sometimes  indicated  by  prefixing 
the  term  .sub,  thus  sub-cordate,  sub-sessile,  sub-acute.  Other  inter- 
mediate terms  very  commonly  employed  are  acutish  and  ol)tnsish. 

The  Compound  Leaf.— lii  the  lohed  leaves  which  we  ha\c  already 
examined,  even  the  most  (leei)ly  dixided  of  them,  the  lobes  are  seen  to 
be  connected  with  one  another  at  the  base  by  ])ortions  of  the  conmion 
blade,  so  that  a  complete  division  of  the  blade  into  separate  parts  has 
not  taken  place.     In  the  leaves  which  we  are  now  to  examine,  such 


190 


THE  LEAF 


se])arati()n  has  occurred,  and  the  lamina  has  become  divided  into  a 
number  of  distinct  secondary  bhides  (Figs.  54S,  .554,  etc.).  Leaves  of 
this  kind  are  called  Compound,  and  their  divisions,  Leaflets. 

If  the  leaflets  are  themselves  compound,  the  leaf  is  Decompound. 
Decompound  leaves  are  spoken  of  as  once  compound,  twice  compound, 
etc.,  according  to  the  number  of  successive  divisions.  Leaflets  may  be 
distinguished  from  leaves  by  the  fact  that  no  buds  are  found  in  their 
axils.  Leaflets  are  subject  to  the  ai)i)lication  of  the  same  descriptive 
terminology  as  leaves. 

Leaflets  of  the  first  division  are  called  Pinnae,  those  of  subsequent 
divisions,  Pinnules. 

The  continuation  of  the  petiole  passing  up  among  the  leaflets,  that  is 
the  midrib  of  the  compound  leaf,  is  the  rachis  (6,  Fig.  475). 


Fig.  547.   Palmately  compound  leaf  {Aesculus).    548.  Palmately  trifoliolate  leaf  (Trifolium) .    549. 
Pinnately  trifoliolate  leaf  (.Lespedeza) .    550  and  551.  Unifoliolate  compound  leaves  of  orange. 


When,  as  in  Fig.  548,  the  compound  leaf  has  no  rachis,  its  division 
being  on  the  same  plan  as  the  lobing  of  the  palmatifid  leaf,  it  is  Palmate, 
or  Palmately  compound.  When  the  rachis  does  exist,  corresponding  to 
the  pinnatifid  type  (Figs.  549  and  554),  the  leaf  is  Pinnate,  or  Pinnately 
Compound. 

Before  proceeding  to  define  the  distinct  forms  of  the  two  classes,  we 
note  that  it  is  not  always  possible  to  identify  them  with  readiness.  For 
example,  the  ancestral  form  of  the  leaf  of  the  orange  was  pinnate,  but 
at  the  present  time  we  find  that  only  the  terminal  leaflet  remains, 
there  being  usually  at  the  base  more  or  less  of  an  indication  of  the  two 
lateral  leaflets  which  once  existed  (Figs.  550  and  551).  Such  a  leaf 
cannot,  therefore,  be  properly  designated  as  simple,  and  we  designate 
it  as  a  Unifoliolate  compound  leaf. 

Compound  leaves  with  three  leaflets,  usually  designated  as  Trifolio- 
late, frequently  give  us  considerable  difficulty  in  determining  whether 


77//';   COMl'Oi'MJ   Lh'AF 


191 


tlu'v  arc  i)iiiiiatc'ly  or  ])almatoly  coinpouiKl.  Tlic  (iiu'stioii  is  to  l)e 
decided  in  aeeordaiiee  with  tlie  i)()iiit  a(  wliieii  disarticulation  of  the 
tenniiial  leaflet  occurs.  If  ])alniate,  the  \):\>v  of  the  blade  must  ))e  the 
point  at  which  the  three  petioles  separate,  so  that  when  disarticulation 
occurs  no  rachis  will  remain  extending  l)ey()nd  the  j)oint  of  attachment 
of  the  two  lateral  leaflets  (Fig.  548).    In  the  })innate  form  such  a  rachis 


Fig.  .'io2.  Triternate  leaf.  553.  Pedatetloaf  (violet).  554.  Pari-pinnate  leaflet  of  Gcdilschia.  555. 
Impari-pinnate  leaf  of  rose.  556.  Millifoliolate  leaf  of  Achilldea  557.  Interrupteilly-pinnate  leaf 
of  Aqrimonia.     558.  Runcinate  leaf  of  dandelion.     559.    Lyrate  leaf  of  barbarea. 

(Fig.  549,  a),  although  frequently  very  short,  does  exist.  In  the  family 
Leguminosae,  the  question  of  whether  a  leaf  is  pinnately  or  palmately 
trifoliolate  is  of  fundamental  importance  in  classification. 

A  three-parted  j)almately  com])ound  or  divided  leaf  is  called  Ternate; 
a  five-parted  one  Quinate,  a  se\en-parted  one  Se])tate. 

A  palmatifid  (or  i)alinate)  leaf,  with  very  narrow  di\  isions,  is  called 
Pedate  (Fig.  553). 


192  THE  LEAF 

If  the  divisions  of  such  a  leaf  are  similarly  compound  or  divided, 
appropriate  terms  are  formed,  such  as  Bi-ternate  (Fig.  552),  Tri-ternate, 
and  so  on.  Similarly  named  sub-divisions  of  the  pinnate  form  exist, 
the  bi-pinnate  (Fig.  563),  tri-pinnate  (Fig.  556),  and  so  on. 

These  terms  are  also  sometimes  applied  to  the  similar  divisions  of 
pinnatifid  leaves.  Just  as  we  have  found  that  the  number  of  pairs  of 
primary  veins  of  the  simple  leaf  is  generally  characteristic  of  the  species, 
so  we  find  that  the  number  of  pairs  of  pinnae,  technically  known  as 
Jugae,  is  equally  so.  This  number,  therefore,  should  always  be  stated, 
the  leaf  being  designated  as  Bi-jugate,  Tri-jugate,  Multi-jugate  and 
so  on. 

Two  classes  of  pinnate  leaves  are  recognized,  in  accordance  with 
their  termination  in  a  pair  or  in  a  single  terminal  leaflet.  Those  ending 
in  a  pair  (Fig.  554)  are  called  Pari-pinnate,  Even-pinnate,  or  Equally- 
pinnate,  the  others  (Fig.  555)  Impari-pinnate,  Odd-pinnate,  or 
Unequally-pinnate. 

When  the  divisions  of  a  pinnate  or  a  pinnatifid  leaf  are  alternately 
large  and  very  small  (Fig.  557),  it  is  called  Interruptedly-pinnate  or 
Pinnatifid. 

When  the  leaflets  or  divisions  are  turned  backward  so  that  they 
point  more  or  less  in  the  direction  of  the  base  (Fig.  558),  the  leaf  is 
Runcinate. 

When  the  terminal  division  is  very  much  larger,  especially  broader, 
than  the  lateral,  the  leaf  is  Lyrate  (Fig.  559). 

Modified  Leaves. — Coming  now  to  consider  the  subject  of  character- 
istic modifications  in  the  form  and  function  of  the  leaf,  we  note  that 
some  of  them  pertain  to  the  entire  leaf,  others  to  its  individual  parts. 
We  also  note  that  in  some  of  the  modifications  the  entire  leaf  or  one  of 
its  parts  retains  the  ordinary  functions  of  absorption  and  assimilation, 
the  new  function  being  added  thereto  either  by  partial  change  of  the 
entire  leaf,  or  the  complete  modification  of  one  or  more  of  its  parts, 
while  at  other  times  the  original  functions  are  entirely  lost. 

Carnivorous  Leaves. — The  function  of  absorbing  and  assimilating  the 
ordinary  forms  of  nutriment  is  sometimes  supplemented  by  that  of 
absorbing  and  assimilating  animal  tissue.  In  this  case  the  leaf  pro- 
vides special  forms  of  apparatus  for  enticing,  intoxicating,  or  mechan- 
ically catching,  killing  and  digesting  the  animal,  commonly  an  insect. 

The  Pitcher  Plant. — One  of  these  forms  is  illustrated  in  the  pitcher 
plant  (Fig.  560),  in  which  one  portion  of  the  leaf  becomes  converted 
into  a  vessel  containing  liquid  of  variable  origin  and  complex  compo- 


ETIOLA TED  LEA  YES 


193 


sition.  U])()n  the  outer  portion  of  the  ])itc'her  a  Hue  of  ghiiiduhir  tissue 
stretches  downward.  The  insect  feeds  ujjward  along  this  line  of  secre- 
tion, which  so  changes  its  nature  toward  the  toj)  of  the  pitcher,  that 
by  the  time  the  insect  reaches  that  point  he  is  more  or  less  intoxi- 
cated, and  on  crossing  the  margin,  or  quickly  thereafter,  falls  into  the 
liquid  and  is  drowned,  digestion  prom])tly  occurring  by  means  of 
enzymes  excreted  into  the  liquid  by  special  glands  located  upon  the 
inner  face  of  the  i)itchcr. 


Fig.  560.   Modifitd  (pitcher)  leaf  of  NepeiUhcs.     561.  Modified  leaf  of  Die 


The  Venus' s  Fhj-fntp. — Another  form  is  the  well-known  ^'enus's 
fly-trap  (Fig.  5()1),  which  secretes  a  nectar  by  certain  glands  which 
surround  its  margin.  The  insect,  alighting  upon  this  point,  is  instantly 
seized  through  the  sjiasmodic  coming  together  of  the  two  lateral  halves 
of  the  leaf,  which  act  precisely  like  the  jaws  of  a  trap.  Digestive  fluids 
are  then  immediately  poured  forth  from  special  glandular  tissues  on 
the  leaf-surface  and  digestion  and  absorption  take  i)lace.  That  the 
nutrients  thus  absorbed  are  of  service  to  the  ])lant  has  been  proved  by 
elaborate  experiments,  in  which  the  eflfects  of  such  feeding  have  been 
estimated  by  comparing  their  re})roduction  with  that  of  other  similar 
plants,  similarly  treated  in  all  respects  except  that  they  were  dei)ri\ed 
of  this  form  of  food. 

Etiolated  Leaves. —  In  other  cases,  the  ])lant  being  nourished  by 
means  of  fully  prepared  nutrients  absorbed  from  other  leafy  plants 
(host-plants)  upon  whicli  they  are  parasitic,  the  leaves  lose  the  chloro- 
phyll tissue  uj)()n  which  their  ordinary  functions  (lei)cnd,  and  arc 
known  as  Etiolated  leaves.  They  become  reduced  in  size  and  scale-like 
in  form. 
13 


194 


THE  LEAF 


Plants  which  grow  in  excessively  dry  or  desert  regions,  and  Avhich 
are  thus  ^'ery  liable  to  suffer  from  excessive  evaporation,  ordinaril}- 
have  their  leaves  modified  in  some  way  so  as  to  guard  against  this 


Fig.  562.  Phyllodiuni  of  Aaicia.  503.  Leaf  of  Acacia  with  blade  present.  564.  Loaf  of  Eichomia 
with  inflated  petiole.  505.  Cirrhose  stipules  of  Smilax.  566.  Aculeate  leaf  of  Rubus.  567.  Cirrhif- 
(Tous  leaf  of  pea.  568.  Leaf  of  Tococa,  its  inflated  petiole  the  home  of  ants.  569.  Cirrhose  petiole 
of  Clematis. 

tendency,  and  are  called  Xerophytic.  They  may  become  merely 
reduced  in  size  or  may  be  otherwise  modified,  so  as  to  reduce  the 
amount  or  the  degree  of  activity  of  their  epidermal  tissue,  or  they 


FLORAL  LEAVES  OR  BRACTS  195 

may  disappear  altogether,  or  become  transformed  into  organs  of  a 
different  character.  In  one  of  tliesc  forms  the  leaf  becomes  converted 
into  a  s])ine,  or  a  grou])  of  s])ines,  each  consisting  of  one  of  the  teeth. 
In  this  condition  the  leaf  serves  an  important  function  in  protecting 
the  plant  against  destruction  by  desert  animals. 

Phyllodia. — At  other  times  the  blade  (Fig.  5().'^,  a)  entirely  disappears, 
a  false  blade  (Phyllodium,  Fig.  5()2),  of  much  less  activity  as  an  evapor- 
ating organ,  becoming  formed  by  the  flattening  out  or  exi)ansion  of 
the  petiole  (Fig.  553,  c).  A  phyllodium  is  readil>-  distinguished  from  a 
leaf-blade  in  that  its  broad  surfaces  are  directed  laterally  instead  of 
vertically,  as  in  the  true  lamina. 

Leaves  as  Floating  Organs. — Leaves  or  their  petioles  frequently 
become  luodified  into  floating  organs  in  aquatic  i)lants,  as  in  the  case 
of  the  bladdery-inflated  petioles  of  the  Eichornia  (P'ig.  504). 

Somewhat  similar  inflated  organs  exist  upon  the  petioles  of  some 
plants  and  serve  as  the  homes  of  colonies  of  ants,  which  are  efficient  in 
protecting  the  plant  against  the  attacks  of  certain  animals  (Fig.  568,  a). 

Leaves  as  Climbing  Organs. — The  office  of  climbing  is  frequently 
])crf()rnH'd  by  a  portion  of  the  leaf.  In  some  cases,  as  the  Clematis 
(Fig.  569),  the  petiole  of  the  leaf  becomes  twining  for  this  purpose. 
At  other  times  the  apex  of  the  rachis  (Fig.  567)  becomes  a  tendril, 
either  simple  or  branching,  while  at  others  the  entire  leaf  becomes  thus 
modified.  In  the  Smilax  (Fig.  565)  it  is  the  stipule  which  is  thus 
changed.  In  other  cases  (P'ig.  566)  climbing  is  effected  by  means  of 
hooks  develoi)ed  u])on  some  ])ortion  of  the  leaf. 

Floral  Leaves  or  Bracts. — Besides  protecting  the  i)laut  by  becoming 
converted  into  spines  or  spine-bearing  organs,  as  above  described,  the 
leaf  is  subject  to  various  other  modifications  having  this  object  in  view. 
Ucfert-nce  lias  already  been  made  to  such  modifications  in  the  form  of 
bud  scales.  For  the  i)rotection  of  the  flower  exist  the  epicalyx  and  such 
scales,  called  Floral  Leaves  or  Bracts,  as  have  been  described  in  our 
opening  account  of  the  flowers  of  the  willow. 

Floral  leaves  or  bracts  do  not  always  exist  merely  for  jjurposes  of 
protection.  In  very  many  cases  they  are  functionally  a  i)art  of  the 
flower  structure,  surrounding  either  single  flowers  or  clusters  of 
flowers,  and  ser\ing  by  their  large  size  or  brilliant  coh)rs,  or 
both,  to  attract  insect-\isits,  i)rccisely  the  same  as  has  be(Mi  described 
in  reference  to  the  i)erigone.  Through  the  floral  bracts  thus  modified, 
we  get  a  direct  transformation  into  the  ])arts  of  the  perigone,  as  has 
already  been  sufficiently  explained.     It  is  also  important  to  note  that 


196  THE  LEAF 

a  direct  relation  is  to  be  traced  between  the  definite  arrangements  of 
foliage  and  floral  leaves,  as  will  be  considered  under  Phyllotaxy,  and 
the  arrangement  of  the  parts  of  the  flower  itself;  so  the  characteristics 
or  praefloration  are  seen  to  be  directly  dependent  upon  the  phyllotaxy 
and  praefoliation. 

Phyllotaxy. — In  view  of  the  established  fact  that  the  development 
of  the  branches  follows  that  of  the  leaves,  it  becomes  clear  that  the 
arrangement  of  the  latter  determines  the  entire  symmetry  of  the 
plant,  with  all  the  far-reaching  consequences  in  connection  with  both 
vegetation  and  reproduction.  Certain  definite  laws  of  phyllotaxy 
having  been  ascertained,  the  forms  resulting  become,  in  their  different 
manifestations,  of  nearly  fundamental  importance  in  classification  and 
in  diagnosis. 

The  Whorled  Arrangement. — We  find  that  either  one  or  more  than  one 
leaf  is  developed  from  a  node.  In  the  latter  case  the  arrangement  is 
called  Verticillate  or  Whorled,  and  the  circle  a  Whorl  or  Verticil.  If 
the  Whorl  contain  but  two  members,  they  are  called  Opposite — that 
is,  the  centers  of  their  points  of  insertion  are  separated  by  one-half  the 
circumference,  or  their  Divergence  is  180  degrees.  Usually  the  other 
nodes  are  similarly  clothed,  except  that  in  all  of  the  higher  plants  the 
leaves  of  each  pair  Decussate  with  those  of  each  adjacent  pair — that  is,  a 
leaf  of  one  whorl  is  over  the  center  of  the  sinus  of  that  next  below  (Fig. 
570).  Four  vertical  rows  (Orthostachies)  of  leaves  thus  appear  upon 
such  a  stem  (Fig.  573).  If,  instead,  there  be  three  leaves  to  the  whorlj 
six  orthostachies  will  result;  if  four,  eight;  and  so  on.  It  frequently 
happens  that  the  number  of  leaves  in  the  upper  or  lower  whorls  will 
contain  only  half  the  number  of  leaves  in  the  others,  and  still  higher 
up  the  whorled  arrangement  may  be  lost,  the  leaves  becoming  arranged 
as  in  the  form  next  considered. 

The  Alternate  or  Spiral  Arrangement. — By  the  other  arrangement  the 
nodes  produce  solitary  leaves,  so  that  each  leaf  is  successively  produced 
at  a  higher  level.  If  a  line  be  traced  from  the  point  of  origin  of  one 
leaf  to  that  of  the  one  next  above,  and  continued  in  the  same  direction, 
so  that  it  exactly  meets  the  point  of  insertion  of  another,  and  then  of 
another,  and  so  on,  it  will  at  length  meet  one  exactly  over  the  point  of 
starting — that  is,  a  second  leaf  in  the  same  Orthostachy  (Fig.  571). 
It  will  then  be  found  that  the  line  followed  is  a  spiral,  which  has  passed 
once  or  more  around  the  stem.  Such  a  spiral  is  called  a  Cycle,  and  if  its 
line  be  continued,  it  will  form  other  similar  cycles  above  and  below.  It 
is  observed  that  a  cycle  will  be  limited  by  two  adjacent  leaves  of  one 


THE  ALTERNATE  OR  SPIRAL  ARRANGEMENT 


197 


Ortliostacliy.  Thus,  if  loaf  No.  4  is  the  next  in  tlie  orthostachy,  to 
which  leaf  No.  1  belongs  (Fig.  574),  three  lea^■es  will  belong  to  that 
cycle.  A  cycle  containing  three  leaves  makes  but  one  turn  of  the  stem. 
A  cycle  is  expressed  in  the  form  of  a  fraction,  its  numerator  indicating 
the  number  of  times  it  encircles  the  stem,  its  denominator  the  number 
of  leaves  which  it  includes,  so  that  the  cycle  last  described  must  be 
indicated  by  the  fraction  one-third.  The  angular  divergence  of  its  leaves 
is  120  degrees.  If  the  next  leaf  in  the  same  orthostachy  as  No.  1  be 
No.  G  (Fig.  572),  then  that  cycle  will  contain  five  leaves.  A  cycle 
containing  five  leaves  makes  two  circuits  of  the  stem,  so  that  its  exponent 


Fig.  570.  Decussating  opposite  leaves.  571.  Alternate  or  spiral  leaf-arrangement.  572.  Diagram 
of  the  same,  the  f,  arrangement.  573.  Diagram  of  570,  showing  its  4  orthostachies.  574.  The  j  spiral. 
575.     The  ,;  spiral. 

will  be  two-fifths.  If  the  second  leaf  of  the  orthostachy  were  No.  9,  the 
appropriate  fraction  would  be  three-eighths,  the  cycle  making  three 
turns  and  containing  eight  leaves  (Fig.  575).  It  will  thus  be  observed 
that  these  fractions  form  a  series,  in  which  each  possesses  a  numerator 
equal  to  the  sum  of  the  numerators  of  the  two  preceding  and  a  denom- 
inator equal  to  the  sum  of  the  denominators  of  the  two  preceding.  No 
cycles  occur  among  the  higher  plants  with  which  we  are  concerned, 
which  can  be  indicated  by  any  fraction  not  thus  formed. 

Noticing  these  fractions  still  further,  we  obserxe  that  tlic  (Iciioiiii- 
nators  will  indicate  the  number  of  orthostachies  upon  the  stems  which 


198  THE  LEAF 

they  represent,  and  that  the  value  of  the  fraction  will  represent  the 
divergence  of,  or  part  of  a  circle  between,  any  two  leaves  adjacent  in 
the  cycle  or  spiral — that  is,  the  number  of  degrees  between  such  leaves 
will  equal  that  fractional  part  of  3()0  degrees. 

Antidromy. — As  to  the  direction  which  the  spiral  takes,  it  may  be 
either  from  right  to  left  or  from  left  to  right.  It  is  supposed  that  each 
kind  of  plant,  at  least  of  the  higher  classes,  produces  two  forms  or 
"castes,"  depending  in  some  not  yet  perfectly  determined  way  upon 
the  relative  positions  of  the  respective  ovules  from  which  they  originate. 
The  tendency  of  these  two  castes  to  manifest  their  growth  or  develop- 
ment in  opposite  directions  has  been  called  Antidromy.  Among  numer- 
ous other  phenomena  attributed  to  antidromy  is  this  starting  of  the 
leaf-spiral  in  opposite  directions  in  plants  of  the  two  castes  of  any 
species  with  this  form  of  phyllotaxy. 

The  Scattered  Arrangement. — Occasionally,  leaves  appear  to  be 
irregularly  disposed  upon  the  stem — that  is,  they  are  not  whorled,  nor 
does  the  law  of  alternate  phyllotaxy  appear  to  apply  to  them.  This 
arrangement  is  called  Scattered,  and  the  explanation  is  dift'erent  in 
different  cases. 

Tufted  Leaves. — When  a  stem  is  so  shortened  that  the  leaves  are 
crowded  upon  it  in  the  form  of  a  regular  rosette,  as  in  the  house-leek, 
the  arrangement  is  called  Tufted. 

Fascicled  Leaves. — ^When  similarly  short,  but  the  leaves  few  and 
irregularly  crowded  in  a  little  bunch,  the  arrangement  is  Fascicled. 

The  two  regular  forms  of  leaf  arrangement  above  described  can  be 
traced  in  greater  or  less  perfection  through  floral  bracts  and  involucres, 
and  into  and  in  many  cases  partly  or  wholly  through  the  flower  itself. 
While  such  arrangement  in  the  flower  is  in  many  cases  entirely  verti- 
cillate  and  in  most  cases  partly  so,  it  has  been  quite  clearly  shown  that 
many  flowers  have  certain  of  their  parts  arranged  ui)on  the  spiral  ])lan. 


CllArTKIJ     XVll 
ANTIIOTAXY 

The  aiTangcment  of  flowers  is  called  their  Aiithotaxy,  and  this  name 
is  also  ap})lied  to  the  study  of  inflorescences. 

The  Inflorescence. — That  part  of  a  stem  or  branch  which  bears  the 
flowers,  or  the  flower  when  solitary,  is  more  or  less  distinctly  modified 
in  form,  surface,  modification  of  its  leaves,  extent  and  character  of 
branchinff,  and  frequently  also  in  the  direction  taken  in  the  arrange- 
ment of  its  parts.  In  connection  with  its  flowers  it  is  called  the  Inflor- 
escence. 

The  stem  of  an  Inflorescence,  that  is,  the  portion  which  is  below  its 
lowest  point  of  branching  or  flowering,  or  below  the  flower  when  solitary, 
is  called  the  Peduncle  {a  in  Figs.  57()  and  583).  This  name  is  also 
applied  to  the  corresponding  portion  of  a  branch  of  an  inflorescence  if 
that  branch  bear  more  than  one  flower,  it  being  in  that  case  a  Secondary 
Peduncle  (Fig.  584,  d). 

The  Rachis. — If  the  peduncle  is  continued  above  its  first  point  of 
branching,  in  the  form  of  a  central  support  along  which  the  succeeding 
branches  or  the  flowers  are  arranged,  this  portion  is  called  the  Uachis 
(Figs.  583  above  a  and  58(5,  a). 

The  Scape. — A  peduncle  which  rises  directly  from  or  near  the  ground 
is  called  a  Scape  (Fig.  57(5,  a). 

The  Pedicel. — The  stem  of  one  of  the  iii(h\idual  flow(>rs  of  an  inflor- 
escence of  more  than  one  flower  is  called  a  JVdicel  (r,  in  Fig.  584).  A 
flower  or  an  inflorescence  may  be  devoid  of  i)e(licel  or  ])eduncle,  when 
it  is  Sessile. 

The  arrangement  of  the  infloresc(Mice-lea\es  and  their  lloral  branches, 
while  based  upon  the  phyllotaxy,  and  traceable  thereto  in  most  cases, 
exhibits  more  or  less  real  or  apparent  departure  therefrom,  and  calls 
for  special  designations  and  classification. 

The  Determinate  form  of  Anthotaxy. — The  forms  of  flowering  are 
di\i(led  into  two  scries  in  accordance  with  the  a])ical  or  lateral  location 
of  the  initial  fiower — that  is,  the  flower  which  is  first  in  order  of  develop- 
ment.   If  the  terminal  bud  develop  into  a  flower  (Fig.  57(5)  its  further 


200  ANTHOTAXY 

extension  is  impossible,  except  by  the  rare  and  abnormal  process  of 
Proliferation.  Inflorescences  so  limited  are  called  Determinate  or 
Definite. 

Vertical  Extension  by  the  Branches. — Although  vertical  extension  of 
the  original  stem  of  a  determinate  inflorescence  is  not  possible,  it  can 
take  place  through  the  branches,  the  same  as  in  other  sympodia.  The 
effects  of  such  development  are  the  same  as  in  other  forms  of  sympodial 
growth  in  which  there  is  a  transformation  of  the  apex  of  the  original 
stem — as,  for  instance,  in  our  explanation  of  such  a  mode  of  develop- 
ment of  the  tendril  (Fig.  431).  To  apply  this  principle  in  the  case  of  an 
inflorescence,  we  have  only  to  assume  a  flower  developed  at  the  tip  of 
every  branch  in  Figs.  433  to  435.  Flower  a  would  develop  first;  h, 
although  the  second  in  order,  and  hence  a  branch,  and  afterward  c, 
would  be  more  elevated,  and  would  thus  seem  to  prolong  the  vertical 
extension  of  the  stem.  The  development  being  successively  by  nodes 
whose  original  points  of  origin  were  successively  lower  than  that  of  the 
terminal  flower,  is  structurally  and  really  Descending  or  Basipetal, 
even  though  by  the  upward  growth  of  the  successive  branches  they  be 
at  successively  higher  levels,  the  order  apparently  in  the  opposite 
direction.  By  the  development  at  each  node  of  a  pair  of  opposite 
branches  we  get  the  apparent  bifurcating  or  dichotomous  form  (Fig. 
435).  If  but  one  branch  grow  from  a  node,  and  these  successively  from 
right  to  left,  the  zig-zag  or  Flexuose  form  of  rachis  is  produced  (Fig. 
433),  and  if  constantly  from  the  same  side,  or  apparently  so,  the  Cir- 
cinate  (Fig.  434). 

The  descending  or  basipetal  nature  of  the  definite  inflorescence  is 
clearly  shown  when  the  successive  branches  remain  short,  each  succes- 
sively developed  flower  remaining  at  a  lower  level  than  that  which 
preceded  it  (Fig.  581). 

The  Centrifugal  Form. — Instead,  however,  of  assuming  either  of  these 
two  states,  in  which  the  flowers  remain  at  different  levels,  the  branches 
may  radiate  and  elongate  to  different  degress,  ceasing  their  elongation 
when  their  flowers  have  been  brought  to  a  uniform  height,  so  that  a 
more  or  less  flat-topped  inflorescence  results,  the  order  of  development 
being  from  the  center  outward,  or  Centrifugal,  as  in  the  branches  of 
Fig.  584. 

Cymose  Inflorescences. — This  form  represents  the  true  Cyme,  and 
because  of  their  relationship  to  it  this  entire  series  of  inflorescences  is 
often  denominated  the  Cymose.  It  will  thus  be  seen  that  in  different 
forms  of  the  cymose  inflorescence,  we  may  have  the  flowers  all  brought 


THE  INDETERMINATE  FORM  OF  ANTIIOTAXY 


201 


at  length  to  a  uiiiforni  level,  those  of  successively  later  (leveIo])ment 
brought  to  successively  higher  ])oints,  or  left  at  successively  lower 
le\-els.  This  fact  demonstrates  that  the  cyniose  or  descending  nature 
of  an  inflorescence  cannot  be  determined  by  noting  the  relative  heights 
of  the  flowers  themselves,  but  only  by  noting  the  order  of  their 
development. 


JS2 


MJ. 


J^SJ.  J86 


Fig.  576.  Scapo.sc  1-flowored  peduncle  of  tulip.  577.  Corymb  of  Crataegus.  578.  Head  of  Cepha- 
lantll^ls.  579.  Umbel  of  ^Lscifpias.  580.  Secund  raceme  of  fiicucw/^o.  581.  A  descending  inflorescence. 
582.  Ordinary  raceme.  583.  A  spike.  584.  Compound  cyme  of  Saponaria.  585.  Globular  spadix 
enclosed  in  spathe  of  Spathyema.    586.  Cylindrical  spadix  of  Acorus. 


The  Indeterminate  Form  of  Anthotaxy. — In  the  second  series,  the  first 
flower  to  develop  is  structurally  the  lowest  of  the  cluster,  the  succession 
being  upward.  Ascending  or  Acropetal  (Figs.  582  and  583).  If  the 
successive  branches  develop  less  rapidly  than  their  predecessors, 
the  result  is  again  a  flat-topped  inflorescence,  with  the  development 
from  the  outside  to  center,  or  Centripetal  (Figs.  577  and  579).  The 
branches  and  flowers  may  be  separated  on  obvious  peduncles  and 
pedicels,  or  these  may  be  not  apparent,  the  flowers  being  sessile.  In 
accordance  with  the  characters  above  explained,  we  obtain  the  following 
simple  forms  of  anthotaxy: 


202  ANTHOTAXY 

Series  1 

Ascending,    Acropetal,    Indefinite,    Indeterminate,    Centripetal,  or 
Botryose  Forms. 

A.  With  the  rachis  not  elongated. 

1.  The  Capitulum  or  Head,  with  the  flowers,  and  branches, 

if  any,  sessile  or  so  regarded  (Fig.  578). 

2.  The  Corymb,  with  the  rachis  manifest,  though  short,  and 

its  pedicels  or  branches  elongated  so  as  to  produce  a 
flat-topped  inflorescence  (P'ig.  577). 

3.  The  Umbel,  similar  to  the  Corymb  but  with  the  rachis 

not  manifest,  so  that  the  pedicels  or  branches  all  appear 
to  start  from  one  point  at  the  summit  of  the  peduncle 
(Fig.  579). 

B.  With  the  rachis  elongated. 

4.  The  Spike,  with  the  flowers,  or  branches,  if  any,  sessile  or 

so  regarded  (Fig.  583). 

5.  The  Catkin  or  Ament,  a  spike  with  slender  rachis  and 

bearing  usually  staminate  or  pistillate  flowers,  crowded 
and  subtended  by  scales  (Figs.  8,  11,  and  15). 

6.  The  Raceme,  similar  to  the  spike  or  ament,  but  having 

the  flowers  pedicelled  (Figs.  580  and  582). 
When  either  the  head  or  spike  possesses  a  thick,  fleshy, 
rachis  it  is  called  a  Spadix  (Figs.  585  and  586). 

Series  2 

Descending,  Basipetal,  Definite,  Determinate,  Centrifugal,  or  Cymose 
Forms. 

1.  The  Glomerule,  corresponding  to  the  head  in  all  respects 

save  that  the  central  flower  first  develops. 

2.  The   Fascicle,    similar   to   the   glomerule   except   that   the 

flowers  are  few  and  loosely  clustered. 

3.  The  Cyme,    similar  to  the    corymb    or  umbel,  save    that 

the  central  flower  is  the  first  to  develop  (Fig.  584). 

4.  The   Scorpioid    Raceme.      Similar   to   the   raceme,    except 

that  each  successive  node  and  flower  upward  is  lateral  to 
that  next  below.  The  apex  of  the  scorpioid  raceme  is 
circinately  coiled  (Fig.  434). 


THE  ANTIIODIUM  203 

Compound  Inflorescences. — Before  ])r()ceeding  to  consider  certain 
speciul  forms  and  inodificatioiis  of  the  inflorescences  above  defined, 
it  should  he  remarked  that  most  of  the  forms  may  be  comi)ouiid.  By 
this  we  mean  that  the  chister  is  made  up  of  a  number  of  l)raneiies  whose 
order  of  devel<)i)ment  is  the  same  as  that  of  the  elements  of  which  they 
are  composed.  That  is,  the  raceme  may  i)ossess  a  number  of  branches, 
each  of  wliicli  is  a  smaller  or  secondary  raceme,  or  if  not  a  raceme,  at 
least  a  small  inflorescence  of  the  ascending  or  centripetal  form.  Similarly, 
an  umbel  may  be  made  up  of  branches,  each  of  which  is  a  smaller  umbel, 
the  Umbellule.  A  cyme  will  be  made  up  of  cymules,  and  so  on.  A 
Panicle  is  a  compound  raceme  which  assumes  the  form  of  a  pyramid. 
Any  form  of  inflorescence  not  a  true  panicle,  but  assuming  the  shai)e 
of  one,  is  styled  Paniculate. 

Complex  Inflorescences. — Complex  forms  of  inflorescence  differ  from 
the  compound  in  that  the  order  of  development  of  the  several  flowers 
upon  a  branch  is  of  a  different  kind  from  that  of  the  several  branches 
themselves.  For  exmaple,  the  ThjTsus  or  Thyrse  is  a  paniculate  form 
in  which  the  lowest  branch  is  the  first  to  develop  flowers,  so  that  the 
order  of  development  of  the  branches  is  ascending,  but  within  a  branch 
the  terminal  flower  will  be  the  first  to  develop,  so  that  the  order  of 
development  of  its  flowers  is  descending.  In  the  same  way,  each 
branch  of  an  umbel  may  terminate  in  a  head;  or  we  may  have  a  fascicle, 
each  branch  of  which  is  a  raceme. 

The  Anthodium. — The  term  Anthodium  has  already  been  defined  in 
considering  the  forms  of  the  fruit,  under  Multiple  or  Collective  Fruits. 
The  same  term  is  a])plied  to  an  inflorescence  yielding  the  collective 
fruit  of  that  name  (Fig.  587).  It  is  in  reality  nothing  more  than  a  head 
closely  subtended,  surrounded  or  enclosed  by  an  involucre  (a).  The 
anthodium  is  characteristic  of  the  great  family  Compositae,  and  is  of  so 
much  importance  in  classification  that  its  modifications  call  for  special 
attention.  The  involucre  should  be  studied  as  to  whether  it  is  single, 
double,  or  multiple — that  is,  whether  it  consists  of  one,  two,  or  more 
circles  of  scales;  as  to  whether  these  are  equal  in  length  or  whether  the 
outer  or  inner  are  successively  shorter;  whether  they  are  entirely  free 
and  distinct,  or  adnate  by  their  bases  or  comiate  by  their  margins;  as 
to  whether  they  are  appressed,  or  with  more  or  less  of  their  apical 
portions  recurved  or  spreading;  esi)ecially  as  to  the  general  ft)rm  of 
the  involucre  as  a  whole,  the  terms  used  being  the  same  as  those  i)re- 
viously  applied  to  the  perigone,  and  as  to  the  characters  of  the  individual 
scales,  these  being  })ractically  the  same  as  those  which  have  already  been 
considered  in  connection  with  the  leaves.     The  Ixxiy  consisting  of  the 


204 


AN T HOT AX Y 


combined  tori  of  all  the  flowers  of  the  anthodium,  is  called  a  Receptacle 
(b).  It  is  to  be  studied  as  to  its  being  solid  or  hollow;  as  to  its  general 
form,  and  especially  the  form  of  its  upper  surface,  whether  concave, 
plane,  convex,  rounded,  or  conical;  as  to  its  being  smooth  in  surface, 
honeycombed  or  otherwise,  pitted  (foveolate),  and  if  the  latter,  the 
special  characters  of  the  pits  and  their  margins;  and  as  to  its  being  naked 
or  clothed  with  hairs  or  scales,  and  the  characters  of  the  latter  in  their 
every  detail.  The  head  is  then  to  be  considered  as  to  the  character  of 
its  flowers.  If  these  are  all  sexually  similar,  the  head  is  said  to  be 
Homogamous;  if  different,  Heterogamous.  If  the  flowers  are  all  ligu- 
late,  the  head  is  Liguliflorate.  If  it  possess  a  disk  (e),  of  tubular  flowers 
(d),  it  is  Discoid.    If  this  disk  is  surrounded  by  one  or  more  circles  of 


Fig.   587.     Vertical   section    through   an   anthodium:   a,  involucre;   b,  receptacle;   c,   disk;   d,  disk- 
flower;   e,  ray-flower. 


ligulate  flowers  called  Rays  (e),  it  is  Radiate.  If  the  ray-flowers  and 
disk-flowers  are  of  the  same  color,  the  head  is  Homochromous;  if 
different,  Heterochromous.  The  flowers  must  next  be  studied  as  to 
their  sex.  The  ray-flowers  are  commonly  pistillate,  while  the  disk- 
flowers  are  perfect,  or  the  disk-flowers  may  vary  among  themselves  in 
this  particular.  Very  commonly,  the  ray-flowers  are  entirely  neutral. 
Even  if  pistillate,  they  may  be  sterile.  If  both  classes  of  flowers  are 
fertile,  the  akenes  which  they  produce  may  be  heteromorphous,  those 
of  the  disk  being  commonly  compressed,  those  of  the  rays  commonly 
triquetrous.  Occasionally  the  heads  are  dioecious  or  monoecious.  In 
one  tribe  of  the  Comjjositae  the  corollas  are  bilabiate.  The  character 
of  the  pappus  (Figs.  74  to  83)  is  invariably  of  the  utmost  importance. 


INFLORESCENCE-LEAVES  OR  FLORAL  LEAVES  205 

as  are  the  forms  of  tlie  style-branches  and  the  api)enfhiges  l)oriie  by 
these  at  the  apex  and  by  the  anthers  at  apex  and  at  l)ase  (see  Anth'oe- 
ciuni  and  Gynaeciuni). 

Inflorescence-leaves  or  Floral  Leaves.-Many  special  terms  are  applied 
to  the  forms  of  inflorescence-leaves,  that  is,  the  bracts  subtending  its 
branches  and  the  ])edicels  of  the  flowers,  as  wellas  those  borne  upon 
the  pedicel.  Ordinarily  they  are  conspicuously  smaller  than  the  other 
leaves  borne  by  the  ])lant. 

With  this  reduced  size,  other  modifications  are  noticeable,  csj)ccially 
the  shortening  or  loss  of  the  petiole  and  a  general  tendency  toward 
reduction  to  the  scale-form,  this  tendency  counteracted  in  variable 
degree  by  a  contrary  tendency  to  preserve  the  characteristic  leaf-form. 
These  leaves  are  commonly  spoken  of  as  the  Reduced  Leaves  of  the 
Inflorescence.  To  this  class  belong  the  leaves  of  the  in\-olucre  and  the 
scales  often  found  upon  the  receptacle  of  the  anthodium  already  con- 
sidered. Individually,  they  are  spoken  of  as  bracts,  the  secondary  ones 
bractlets,  and  the  ultimate  very  small  ones  bracteoles.  Ordinarily  the 
changes  here  outlined  as  marking  the  development  of  the  foliage-leaves 
into  the  inflorescence-leaves  are  gradual,  but  in  many  cases  there  is  an 
abru])t  transition  from  the  one  form  to  the  other. 

A  circle  or  cluster  of  bracts  at  the  base  of  an  inflorescence  is  termed 
an  Involucre,  and  this  term  is  also  applied  to  a  single  very  large  bract 
occupying  the  same  position,  although  this  is  more  commonly  known 
as  the  Spathe.  In  most  cases  the  modifications  of  lca\es  forming  the 
scales  of  involucres  are  entirely  dift'erent  from  those  of  bracts  occin-ring 
singly.  They  are  usually  much  larger  than  such  bracts,  their  form  is 
usually  specialized  in  some  way,  and  they  are  very  frequently  highly 
colored,  serving  the  same  purpose  as  neutral  flowers.  The  l)racts  of 
involucres  are  often  amalgamated  so  as  to  form  a  cu])  or  tube. 

Many  one-leaved  involucres  are  very  peculiar,  and  their  mori)holog>- 
even  more  difficult  to  understand.  The  supposed  leaf  is  sometimes  a 
phyllocladium.  In  some  cases  the  flower  appears  to  rise  out  of  the 
modified  or  unmodified  leaf  itself,  as  in  the  Tilid,  the  explanation  in 
these  cases  probably  being  that  adiiation  exists  between  tlie  inflores- 
cence and  the  leaf. 

One  group  of  Families,  the  grasses  and  grass-like  plants,  do  not 
possess  any  obvious  perigone,  its  place  b(>ing  snp]ih'ed  by  peculiarly 
formed,  adapted,  and  arranged  bracts,  in  tlic  form  of  scales  or  chafl", 
and  technically  called  Glumes,  which  give  to  this  gronj)  of  families  the 
title  Glumaccae.  In  the  rushes,  these  glumes  really  are  a  true 
perigone,   whicli    is   trinierous.       In    the   sedges    (Family    Ci/pcrarcoe, 


206 


ANTHOTAXY 


Fig.  588)  the  scales  (a)  are  solitary,  subtending  each  flower.  In  the 
grasses  (Family  Gramincae)  the  glumes  are  arranged  in  pairs,  each 
pair  subtending  a  short  branch,  which  may  bear  only  one,  several,  or 
many  flowers,  the  whole  known  as  a  Spikelet  (Fig.  589).  Typically, 
there  is  besides  the  two  glumes  of  the  spikelet  (a)  an  additional  pair 
of  scales  (c)  for  each  flower  (6).  Thus,  if  there  be  but  one  flower  in  a 
spikelet,  it  possesses  two  pairs  of  scales.  If  more  than  one,  then  there  is 
a  separate  pair  of  scales  for  each  flower,  besides  the  one  pair  pertaining 
to  the  spikelet  as  a  w^hole.     The  scales  of  the  spikelet  are  called  the 


Fig.  588.  Distichous  arrangement  of  flowers  of  a  sedge,  each  scale  (o)  containing  a  flower  {b).     .589. 
Spikelet  from  the  inflorescence  of  a  grass:  a,  glumes  of  the  spikelet;   t,  a  flower;   c,  palets  of  the  flower. 

Glumes,  Glumes  Proper,  or  Lower  Glumes;  those  of  the  individual 
flowers  (c)  Palets  or  Upper  Glumes.  Much  complexity  in  the  relations 
of  the  glumes  ensues  as  a  result  of  suppression  of  both  glumes  or  both 
palets,  of  one  of  either  or  of  each,  or  of  two  of  one  and  one  of  the  other, 
and  so  on.  The  character  of  the  individual  glumes  must  be  carefully 
studied,  as  in  the  case  of  the  involucral  scales  of  the  anthodium.  The 
character  of  the  terminal  appendages  wdiich  they  bear  is  of  special 
importance. 

With  this  study  of  the  inflorescence  we  are  brought  again  to  the 
individual  flower,  with  the  study  of  which  we  commenced. 


CHA  VTKU    X  \M  I  I 
GENERAL  CHARACTERS  OF  CRYPTOGAMS 

Essential  Characteristics. — The  essential  characteristic  of  tlie  flower, 
distinguishing  it  from  all  other  similar  reproductive  structures,  is  its 
possession  of  a  special  tissue  which  constitutes  a  soil  in  which  the 
microspore  germinates,  and  in  which  the  male  gametophyte  develops 
and  grows.  Plants  destitute  of  such  an  organ  are  therefore  knowm  as 
Flowerless  Plants,  An  equally  great  or  even  greater  distinction  is 
found  in  the  fact  that  the  embryo  of  such  plants,  resulting  from  the 
conjunction  of  the  male  and  female  gametes,  is  not  located  in  a  resting 
body  (the  seed),  but  must  continue  its  uninterrupted  development  into 
the  sporophyte.  They  are,  therefore,  often  designated  as  Seedless  Plants. 
Flowerless  or  seedless  plants  are  technically  known  as  cryptogams. 

Alternation  of  Generations. — Our  account  of  the  development  and 
reproduction  of  Phanerogams  has  shown  that  each  individual  passes 
alternately  through  two  difi'erent  forms  of  life,  each  of  which  is  repre- 
sented by  its  characteristic  body  form.  Those  plants  which  present 
themselves  conspicuously  to  view  as  trees,  shrubs,  and  herbs  are  sporo- 
phytes,  producing  spores  in  ovules  and  anther  cells,  these  spores  ger- 
minating to  produce  respectively  the  male  and  female  gametophytes, 
which  constitute  the  other  form  of  the  plant  body,  or  the  alternating 
generation,  and  which  are  too  minute  to  be  seen  with  the  naked  eye. 
The  sexual  elements  borne  u{)on  these  gametophytic  plants  unite  to 
produce  an  embryo  which  is  the  young  body  of  a  new  sporophytic 
generation,  and  which  is  enclosed  in  the  seed.  Such  an  alternation  of 
generations  occurs  also  among  Cryptogams.  In  some  cases  the  incon- 
spicuous generation  is  the  gametophyte  (Fig.  599),  as  in  Phanerogams; 
in  other  cases  the  relations  are  reversed  in  this  regard  (Fig.  59G). 
Among  many  of  the  lower  forms  this  process  does  not  occur,  each  ])lant 
always  reproducing  to  form  a  body  exactly  like  itself,  witii  no  indica- 
tion of  generations  ])resenting  distinct  forms. 

The  Cryptogamous  Plant-body. — (ireat  as  arc  the  dillerences  seen 
among  Phanerogams,  e\en  greater  ones  are  to  be  seen  among  those  of 
Cryptogams.  They  freciuently  present  themselves  as  herbs,  shrubs 
and  trees,  with  wcll-(ieveloj)e(l  leaves,  borne  upon  regularly  occurring 
phytomers.    In  other  cases,  the  stem-structure  is  well  developed,  while 


208  GENERAL  CHARACTERS  OF  CRYPTOGAMS 

the  leaves  are  rudimentary  in  ditt'erent  degrees,  from  those  which 
want  only  the  most  perfectly  develoi)ed  leaf-structure  to  those  which 
are  mere  scales,  consisting  of  a  single  layer  of  flattened  cells.  By  far 
the  greater  number,  comprising  the  lower  classes,  have  nothing  which 
can  be  described  as  homologous  with  the  leaf,  the  plant  consisting  of  a 
simple  body  which,  presenting  many  different  kinds  and  degrees  of 
variation  in  form,  habit,  and  function,  yet  never  shows  any  indication 
of  the  regularly  jointed  structure  characteristic  of  the  higher  plants, 
nor  any  leaves. 

Equally  great  is  the  variation  observed  among  the  roots.  Many  of 
the  higher  forms  possess  true  absorbing  roots,  but  probably  a  great 
majority  of  roots  among  Cryptogamous  plants  are  false  roots  or  rhizoids, 
existing  for  purposes  of  fixation  only. 

Lacking,  as  these  plants  do,  the  elaborate  structures  whose  character- 
istics have  enabled  us  to  identify,  describe,  and  classify  the  higher 
plants,  we  are  obliged  to  look  for  such  characteristics  among  the  differ- 
ent arrangements  of  their  cells.  Since  this  work  requires  the  aid  of 
the  compound  microscope  and  considerable  technical  skill,  entirely 
new  methods  of  examination  become  necessary.  We  do  not,  therefore, 
find  it  practicable  to  consider  them  in  detail  here. 

The  cellular  structure  of  these  plants  may  extend  itself  in  the  three 
directions  of  solid  bodies,  giving  us  masses  of  tissue,  or  they  may  multi- 
ply in  two  directions  only,  giving  us  flat  or  superficial  bodies,  or  they 
may  be  joined  merely  end  to  end,  producing  filamentous  forms.  These 
bodies  may  each  constitute  a  single  plant,  or  their  cells  may  cohere 
merely  by  habit,  each  living  equally  well  if  separately  detached ;  or  they 
may  normally  live  in  a  separated  condition,  thus  giving  us  perfect  plant 
bodies,  each  consisting  of  but  one  cell,  the  unicellular  plant. 

These  imicellular  plants,  furthermore,  vary  most  widely  in  their 
own  structural  characters.  They  may  be  of  microscopical  size,  or  they 
may  become  many  feet  in  length.  They  may  possess  the  simplest 
structure,  or  they  may  develop  large  cavities,  which  are  divided  and 
subdivided  by  processes  developed  from  the  wall,  and  be  shaped  into 
remarkable  forms,  yet  without  true  cell  division  or  multiplication. 

Vegetation. — Regular  vegetative  processes  are  of  course  required 
wherever  growth  occurs,  wherefore  we  must  look  for  them  among  even 
the  simplest  forms.  In  many  cases,  these  processes  are  as  simple  as  the 
bodies  themselves.  Absorption  from  a  surrounding  fluid  medium  by 
the  entire  body  of  the  plant,  with  the  simplest  of  chemical  transforma- 
tions, may  exist,  or  roots  or  other  special  organs  of  absorption,  with 


REPRODUCTION  209 

coniplicated  systems  of  metaholism  and  conduction,  may  l)e  developed. 
Chlorophyll  is  present  in  the  higher  groups,  and  the  vegetative  processes 
are  very  similar  to  those  which  we  have  before  considered.  In  other 
classes  chlorophyll  is  wanting,  and  the  plants  are  hence  unable  to 
perform  the  constructive  assimilation  which  we  have  found  among 
most  Phanerogams,  but  ready  formed  compounds,  or  those  readily 
broken  down  into  the  required  form,  must  be  found  for  their  support. 

Reproduction. — We  find  among  the  reproductive  processes  in  Crypto- 
gams almost  as  great  a  diversity  as  among  their  other  characters.  Not 
only  do  both  vegetative  and  sexual  forms  exist,  as  among  Phanerogams, 
but  while  many  groups  exhibit  both  forms,  others  possess  only  the 
vegetative.  Among  the  higher  classes,  the  vegetative  forms  of  repro- 
duction are  quite  elaborate,  involving  phytomer-like  parts,  either  singly 
or  in  bud-forms,  while  in  other  cases  it  can  occur  by  single  leaves  or 
parts  of  them.  Among  the  lower  classes,  where  phytomers  and  leaves 
are  unknown,  these  processes  are  necessarily  simpler.  In  their  higher 
members,  masses  of  tissue,  often  specially  constructed,  called  gemmae  or 
buds  (but  of  course  not  conspicuously  homologous  with  the  buds  which 
we  have  studied),  separate  to  form  new  plant-bodies,  the  process  being 
called  gemmation.  In  other  cases  the  process  is  the  simplest  possible 
one  of  cell-division. 

Sexual  reproduction  among  cryptogams  is  too  variable  to  be  here 
considered,  even  in  a  general  way.  In  no  Cryptogamous  plant,  how- 
ever, is  there  developed  any  structure  which  combines  the  varied 
functions  of  that  which  among  Phanerogams  is  called  the  flower.  The 
extension  of  this  term  to  any  reproductive  organ  of  the  former  group, 
merely  because  certain  homologies  have  been  discovered  between 
them  and  the  flower,  is  misleading,  as  it  tends  to  magnify  slight  resem- 
blances into  a  higher  degree  of  importance  than  great  differences,  and 
it  furthermore  subverts  the  original  and  fully  established  meaning  of  a 
common  term  into  a  new,  even  if  it  were  a  strictly  accurate,  application. 

When  alternation  of  generations  occurs,  with  the  production  of 
distinct  gametophytes,  the  male  cells,  in  the  form  of  antherozoids,  are 
usually  i)rovided  with  some  independent  power  of  locomotion  for 
reaching  the  female  element,  known  as  the  Central  ( 'ell,  within  a  tlistinct 
organ  called  by  various  names. 

It  has  already  been  stated  that  the  spores  germinate  for  the  ])r()duction 
of  these  gametoi)hytes  in   any  suitable  soil,   and  that  the  resulting 
embryo  continues  its  development  without  passing  into  a  resting  or 
seed  stage. 
14 


210  GENERAL  CHARACTERS  OF  CRYPTOGAMS 


PRINCIPAL  GROUPS  OF  CRYPTOGAMS 

The  main  groiii)s  of  the  cryptogams  are  indicated  in  the  following 
table: 

1.  Thallophyta  or  Thallophytes. 

(a)  Fungi. 
(6)  Algae, 
(c)  Lichenes  or  Lichens. 

2.  Bryophyta  or  Bryophytes. 

(a)  Hepaticae  or  Liverworts. 
(6)  Musci  or  Mosses. 

3.  Pteridophyta  or  Pteridophytes. 

(a)  Eqiiisetaceae  or  Horse-tails. 
ih)  Lycopodiaceae  or  Club-mosses, 
(c)  Filices  or  Ferns. 

Each  of  these  groups  will  be  briefly  considered,  in  so  far  as  relates 
to  its  contributions  to  the  materia  medica. 

Thallophyta.— r/^e  Fungi. — The  Fungi  comprise  plants  destitute  of 
true  chlorophyll,  and  therefore  incapable  of  building  up  their  own 
food  from  elementary  substances.  Their  structural  and  physiological 
characters  are  exceedingly  varied. 

To  the  Fungi  belong  the  Bacteria,  contributing  the  great  majority 
of  disease  germs,  in  the  special  uses  of  which  we  are  yet  to  find  the 
most  important  part  of  our  materia  medica.  The  study  of  this  group 
pertains  to  the  subject  of  Bacteriology. 

To  the  F'ungi  belong  also  the  yeast  plants,  valuable  medicinal  agents, 
but  unicellular,  and  to  be  studied  only  in  the  microscopical  laboratory. 

Among  the  drugs  of  interest  to  commercial  pharmacognosy,  occur 
only  Kefir  grains,  Taka-diastase,  Ergot,  and  the  Agarics,  all  of  which 
belong  in  the  higher  divisions  of  the  group. 

The  vegetative  portion  of  the  Fungi  consists  of  a  tissue  called 
Micelium,  formed  of  filaments,  often  growing  into  large  and  dense 
masses.  In  many,  this  micelium,  after  forming  into  a  hard  mass, 
becomes  dormant,  and  constitutes  a  resting  body  called  the  Sclerotium 
{e.  g.,  Ergot),  which  later,  under  suitable  conditions,  gives  origin  to  the 
spore-bearing  body.  Some  of  the  Fungi  have  no  higher  mode  of  repro- 
duction than  that  of  simple  division  (fission),  although  almost  all  of 
them  reproduce  by  means  of  spores.    These  spores  are  borne  in  various 


rilALLOPIIYTA 


211 


ways  (Fig.  591),  as  to  both  their  minute  and  conspicuous  structures. 
In  the  higher  forms,  such  as  tlie  mushrooms,  tliis  ])ocly  consists  of  a  stem 
bearing  a  cap  or  Pileus  (Fig.  590,  a),  wliich  bears  tlie  si)ores  under- 
neath, on  gills,  teeth,  or  some 
simihir  support  (Fig.  591). 

The  Algae.— The  Algae 
are  almost  without  rei)re- 
sentation  in  the  materia 
medica,  although  they  yield 
important  food  supplies, 
especially  in  Japan.  P^ven 
Chondrus,  the  most  impor- 
tant member  in  drug  com- 
merce, is  in  reality  only  a 
food,  while  Fucus  acts  ratlicr 
by  inorganics,  absorl)ed  by 
it  from  the  sea-water,  than 
by  any  organic  princi])lc  of 
its  own. 


Fig.  590.  Amanita  phalloides. 


Fig.  591.  Showing  parts  of  Mushroom— .4oaric«s 
{FsalUola)  campestris:  A,  a  section  across  a  number  of 
gills,  h;  the  hymenophore,  /;  the  lamellae  or  gills,  one  of 
which  is  more  highly  magnified  in  B,  t,  the  central  hyphal 
tissue;  liy,  the  /li/mivuiaH,  or  spore-bearing  surface;  C,a 
portion  of  gill  still  more  highly  magnified,  //  the  hyphae, 
q;  the  basidia  upon  which  the  conidia  or  spores  are  borne, 
s,  s',  »■" — conidia  in  different  stages.     (Sachs.) 


The  Algae  are  essentially  atiualics,  and  diU'cr  from  the  Fungi  in 
possessing  chloro})hyll  or  some  similar  substance,  by  which  they  are 
enabled  to  l)uil(l  up  their  food  sui)i)lics  from  inorganic  matter. 

The  last  nicnti()iu>d  plant  is  among  the  liighcst  of  this  class.  The 
thallus,  or  ])lant  body  (Fig.  592),  coiisi.Ntiiig  of  a  loose  aggregation  of 
single  cells,  has  a  well-developed   foot,  tl.e  di-k.  by  which  it  clings  to 


212 


GENERAL  CHARACTERS  OF  CRYPTOGAMS 


rocks.    The  stem  is  branching  and  bears  the  reproductive  bodies  (Fig. 
593)  at  the  ends  of  its  branches. 


Fig.  592.  Rock  Weed,  Fucus:  A,  portion  of  branch  bearing  reproductive  organs,  /;  B,  an  enlarged 
section  through  a  reproductive  organ,  the  female  conceptacle,  showing  egg  cells,  c;  the  cavity,  b; 
false  parenchymatic  tissue,  d.    (After  Thuret.) 


LAJ 


^^^#^'- 


Fig.  593  The  sexual  organs  of  Fucus  4,  the  antheridia,  or  male  organs,  a,  borne  on  paraphyses; 
B,  antherozoids  or  gametes,  /,  the  oogonium  or  female  organ,  og;  paraphyses,  p;  II,  the  oospores 
(oospheres),  preparing  to  be  set  free;  ///,  a  free  oospore,  being  fertilized;  IV,  V,  young  Fucus  plants. 


THE  BRYOl'IlYTA 


213 


DillVroiit  sexes  are  hoi'iu'  on  dillci-ciit  ])laiits.  The  t'einale  uv\:;\\\ 
consists  of  a  number  of  sini])Ie  ovaries  ((Jogonia)  (Fig.  592,  c;  Fig,  593, 
ocj),  grouped  together  in  a  Conceptacle.  Eacli  oogonium  contains  eight 
Odsplieres.  These  oospheres  are  set  free  and  are  fertiHzed  by  motile 
Gametes,  tlie  Antherozoids,  which  are  produced  in  conceptacles  of 
another  plant. 

The  Lichens. — Most  systematists  now  regard  the  Lichens  as  belonging 
to  the  Fungi.  They  may  be  defined  as  Fungi  parasitic  on  certain 
Algae.  In  this  form  of  parasitism  each  plant  supplies  some  indispen- 
sable contribution  to  the  other,  the  relation  being  therefore  called  wSym- 
l)iosis.  ^riie  body  of  the  Lichen,  more  particularly  in  the  larger  forms, 
is  made  uj)  of  the  Fungus  mycelium  (Fig.  595,  sh).    The  thallus  may 


Fid.  594.  Concral  viow  of  several  Lichens:  A,  crustaceous  (Graphis);  B,  a  portion  of  this  samelichen 
more  highly  magnifiod,  showing  apothecia;  C,  a  crustaceous  lichen,  Pcrtusaria;  D,  a  sub-foliaceous 
thallus  of  Parmdia  with  numerous  spore-bearing  bodies,  apothecia.     (Sachs.) 


be  large  and  flat,  leathery  and  leaf-like  (foliaceous.  Fig.  594,  D),  or 
upright  and  branching  (fruticose),  or  close-clinging  to  the  bark  of 
trees,  looking  like  a  colored  stain  on  rocks  (crustaceous,  Fig.  594,^1,  O- 
Li  most  cases  the  spores  are  born,  eight  together,  in  little  sacs  called 
Asci,  which  are  themselves  reproduced  in  variously  colored  dosed  or 
open  A])()th('cia  (Fig.  594,   D). 

The  Bryophyta. — Li  this  class  the  cons])icuous  generation  is  the 
gametophyte  which,  in  the  higher  divisions  (left  hand.  Fig.  59(5), 
becomes  a  well-developed  plant  with  stem  and  leaves.  Its  male  repro- 
ductive organs  are  the  Antheridia  (Fig.  597,  a);  its  female  are  the 
Archegonia.  The  efl'ect  of  reproduction  is  the  j^roduction  of  an  embryo, 
which  immediately  germinates  while  upon  the  gametophyte,  sending 
its  foot  down  into  the  tissue  of  the  latter,  and  developing  upward  into 


214 


GENERAL  CHARACTERS  OF  CRYPTOGAMS 


a  sporophyte  (Fio:.  596,  .9,  /,  c),  wliicli  is  tlie  Capsule.  These  ripened 
spores,  in  turn,  germinate  to  produce  a  new  gamet()i)hyte  which,  in  its 
embryonic  state,  is  called  the  Protonema.    It  will  be  observed  that  the 


A 


fA\ 


Fig.  595.  An  Ascomycetous  Fungus — Peziza — 
A,  showing  section  through  complete  spore- 
bearing  body — the  apothecium;  h,  tlie  hyme- 
nium:  s,  the  hyphae,  forming  false  tissue;  B, 
enlarged  section  of  a  portion  of  above  showing 
a,  b,  c,  d,  e,f,  asci,  in  various  sizes  and  in  various 
stages  of  spore  development  taking  place  within 
them,  spores  are  mature  in  /,  sh,  the  false  paren- 
chyma made  up  of  intertwining  hyphae. 


Fig.  596.  Showing  the  development  of  sporo- 
phyte of  moss:  St,  apex  of  stem,  bearing  the 
female  organs;  o,  the  archegonia;  from  these, 
after  fertilization,  the  young  capsules  spring, 
C,  S,  V;  C,  the  calyptra;  underneath  which  is 
found  lid  or  operculum;  /,  the  capsule;  s,  the 
leafless  stem  of  sporophyte  or  pedicel.     (Frank.) 


relative   positions   of   sporophyte   and   gametophyte  are  exactly   the 
reverse  of  what  they  are  in  the  flowering  plant. 

Although   the  hair-cap  moss  is  somewhat   used    in  medicine,  yet 


THE  PrERIDOPIIYTA 


215 


iieitlier  tlie  TTepatics  nor  Mosses  may  be  considered  as  worthy  of  note  in 
commercial  pharmacognosy.  In  the  Mosses,  the  top  of  tlie  stem  or 
branch  bears  a  number  of  bracts  or  modified  leaves,  which  constitute 
the  Perichaetium.  From  amidst  these  bracts  the  Pedicel  (Fig.  59G,  s) 
rises  from  the  foot  and  bears  the  capsule  upon  its  summit.    Through 


i^*^^,. 


Sli'   /   .1 


^l 


Fig.  507  The  male  organ,  antheridium  of 
mosses  (Funaria):  A,  antheridium,  with  escaping 
antherozoids  (o) ;  B,  a  single  male  element  6,  in 
mother  cell;  C,  free,  with  two  cilia. 


Fig.  598.  Lycopodium:  S.  the  oone-like  spore- 
Wearing  leaves;  B,  an  enlarged  sporophyll  leaf; 
h,  the  blade,  and  sp,  the  sporangium  which  con- 
tains the  spores. 


the  center  of  the  ca])sule  the  Pedicel  is  continued  as  the  Columella,  and 
at  its  summit  it  is  closed  in  until  mature  by  one  or  more  coverings.  By 
a  special  organ,  the  Peristome,  consisting  of  a  number  of  teeth,  it  is 
l)ossible  for  the  capsule  to  be  closed  during  wet  weather  and  opened 
for  the  (listrihiitioii  of  its  spores  when  it  is  dry. 

The  Pteridophyta. — All  three  groups  of  this  division  contribute  more 
or  less  important  articles  to  the  commercial  materia  mcdica. 

Equisetaceae. — In  this  group  again  we  ha\e,  as  in  {\\v  flowering 
plant,  a  gametophyte  which  is  microscopic,  although,  unlike  that  of 
the  flowering  plants,  it  is  produced  entirely  disconnected  from  the 
sporophyte.  From  it  develop  hollow-stennned  i)lants  which  are  com- 
monly known  as  horse-tails  or  scouring  rushes.  The  latter  name  is  in 
allusion  to  the  large  amount   of  silica  produced  in    their  superficial 


216  GENERAL  CHARACTERS  OF  CRYPTOGAMS 

tissues,  on  account  of  which  they  are  frequently  used  for  scouring 
purposes.  Medicinally  they  ha^•e'  practically  no  use,  although  it  is 
said  that  poisonous  properties  exist  in  one  or  more  of  them. 

Lycopodlaceae. — The  club  mosses,  like  the  horse-tails,  are  said  to 
contain  some  poisonous  species,  but  their  interest  in  drug  commerce 
resides  wholly  in  the  use  of  the  spores  of  some  species,  inider  the  name  of 
Lycopodium  or  vegetable  sulphur.  In  the  species  yielding  this  product 
there  are  two  forms  of  leaves,  those  upon  the  fruiting  portion  differing 
materially  from  those  of  the  main  stem  (Pig.  598).  In  this  group  the 
spores  are  all  similar  (Homosporous),  while  in  some  of  the  lower  groups 
they  are  of  two  forms  (Heterosporous).  As  in  the  class  last  considered, 
the  gametophyte  is  microscopic,  while  the  sporophyte  is  the  con- 
spicuous generation.  Upon  the  upper  surfaces,  or  in  the  axils,  of  the 
leaves  of  the  fruiting  branch  the  spore-cases  (Fig.  598,  sp)  are  solitary. 
In  collecting  Lycopodium,  it  is  customary  to  pull  off  these  tops  and 
allow  them  to  dry  thoroughly,  whereupon  the  spores  are  easily  shaken 
out. 

TJw  Filices. — The  ferns  contribute  a  number  of  important  articles 
to  the  materia  medica,  the  principal  of  which  is  Aspidium,  or  Male 
Fern. 

From  a  pharmacognostical  viewpoint,  the  chief  difference  between  the 
ferns  and  the  flowering  plants  is  in  the  stem-structure.  The  main  stem 
is  usually  under  ground,  although  often  aerial  and  sometimes  assuming 
the  dimensions  of  a  shrub  or  tree.  In  the  Hawaiian  Islands  these 
trunks  furnish  timber  for  "large  amd  heavy  planking.  The  peculiarity 
of  the  fern-stem  is  its  possession  of  a  number  of  steles,  each  having 
its  own  endodermis.  As  compared  with  the  stem  of  an  ordinary  dicotyl- 
edon, that  of  the  fern  presents  the  structural  appearance  of  being  a 
fascicle  of  stems,  bound  together  by  an  interstellar  tissue.  This  indica- 
tion is  borne  out  by  the  peculiarities  of  the  structures  which  fill  the 
office  of  the  leaves  of  other  plants,  and  which  are  known  as  Fronds. 
While  thus  taking  the  place  of  ordinary  leaves  and  appearing  to  be 
such,  these  are  seen,  on  closer  examination,  to  be  the  homologues  not 
of  leaves,  but  of  stems,  each  of  them  originating  from  and  representing 
one  of  the  steles  of  the  compound  stem.  There  is,  moreover,  no  such 
division  of  the  stem  into  phytomers  as  we  see  in  the  flowering  plants. 

It  is  not  necessary  to  study  the  main  stem  in  order  to  discover  the 
wide  difference  between  the  leaf  and  the  fern  frond,  for  if  one  but 
watches  the  development  and  behavior  of  fronds,  especially  in  certain 
groups,  as  the  Gleichenias,  he  will  be  struck  by  the  fact  that  it  is,  in  its 


THE  I'  TEHl  DO  I' II Y  TA 


217 


real  iiaturi'.  more  like  a  \ivvvu  and  (lattoiicd  stem  than  a  leaf.  These 
facts  have  led  many  inorplioloyists  to  look  upon  the  fern-frond  as  a 
structure  distinct  in  kind  from  the  leaf. 

In  the  ferns  we  again  find  the  gamet()i)hyte  small  and  inconspicu- 
ous (Fig.  599),  while  the  sporophyte  is  the  generaffon  familiarly  known 
to  us.  These  sporoj)hytes  may  he  herhs,  shrubs,  or  trees,  and  many  of 
them  are  climbers. 


Fig.  599.  Organs  of  reproduction  in  the  ferns:  J,  //,  III  (p),  prothallium  or  gamctophyte;  a,  the 
male  organ,  antheridium  in  various  stages  of  growth  of  antherozoids,  which  in  h  are  sliown  free  and 
provided  with  cilia;  c,  oo.spore  or  egg  cell:  E,  the  archegonium — developing  into  young  fern  plant — h. 


The  sporangia  may  be  borne  on  tlie  lower  surface  of  the  one  form  of 
frond  possessed  by  a  species,  or  the  sporophyll  may  be  entirely  different 
from  the  other  fronds.  In  the  former  case,  the  sporangia  are  grouped 
in  little  masses,  forming  rusty-  or  dark-colored  spots  on  the  surface 
which  are  known  as  Sori  or  Fruit-dots.  These  may  be  naked,  or  partly 
or  wholly  covered  by  the  reflex  and  modified  margin  of  the  frond,  or  by 
special  bract-like  membranes,  developed  from  the  surface  of  the  frond. 
Such  a  membrane  is  called  an  Indusium.  When  the  sporophyll  is  of 
special  form,  the  modes  of  arranging,  enclosing,  or  protecting  the 
sporangia  are  various.  I'pon  these  characters,  and  upon  those  of  the 
sporangia  themselves,  is  chiefly  based  the  classification  of  the  ferns. 


"CHAPTER    XIX 

'BOTANICAL  CLASSIFICATION  AND  ANALYSIS 

Reference  was  made  in  our  introductory  chapter  to  the  object  of 
Systematic  Botany  as  being  the  arrangement  of  plants  in  a  system  or 
series  which  should  indicate  approximately  the  successive  order  of 
their  appearance  in  existence,  that  is,  of  their  development,  or  of  their 
creation,  as  commonly  expressed.  The  Cryptogams  or  flowerless 
plants  undoubtedly  existed  first,  and  from  some  one  or  more  of  their 
sub-divisions  the  flowering  plants  developed.  The  former  are  therefore 
regarded  as  "lower"  than  the  latter,  and  are  treated  as  the  basal  or 
fundamental  division  of  plants.  Similarly,  certain  of  their  divisions 
occupy  the  relation  of  having  existed  before  others  and  of  having  given 
origin  to  them,  and  are  therefore  regarded  as  occupying  the  lower 
positions  in  the  cryptogamic  series.  By  determining  those  relations 
for  the  various  sub-divisions,  we  obtain  grounds  for  arranging  all  the 
cryptogams  in  a  sequence  of  which  it  may  be  said,  in  general,  that  the 
lower  came  first  to  exist  and  the  latter  are  newer  in  creation.  By  apply- 
ing the  same  methods,  the  Phanerogams  are  formed  into  a  similar 
series. 

It  must  not  be  understood  that  these  groups  occupy  an  unbroken 
serial  relation  to  one  another,  like  the  rounds  of  a  ladder.  They  would 
do  so  had  each  group  given  origin  to  only  one  other,  and  had  all  the 
groups  maintained  their  existence,  or  even  left  evidences  of  having 
existed,  so  that  their  relative  positions  could  be  assigned  them.  Instead 
of  this,  a  formerly  existing  group  frequently,  probably  usually,  gave 
origin  to  several  new  forms,  many  of  which  became  the  starting  points 
for  others,  so  that  the  system  is  more  like  that  of  the  branching  of  a 
tree  than  of  a  series  of  steps.  Furthermore,  it  has  frequently  happened 
that  a  recent  form  has  continued  in  existence,  while  that  from  which 
it  originated  has  perished  and  left  no  record.  So  great  an  influence 
have  those  conditions  exerted  that  we  have  various  groups  now  in  exist- 
ence, which  show  no  special  relationship  to  any  other,  and  we  have  to 
assign  them  somewhat  arbitrarily  to  their  positions.  For  thejiliind 
similar  reasons,  our  system  is  at  the  best  faulty  and  incomplete,  and  tlilfr 


SPECIES  219 

nature  of  tlio  case  is  such  tliat  it  i)r()l)al)ly  must  always  remain  so.  In 
spite,  however,  of  all  these  imjierfections,  steady  and  great  progress  has 
been  and  is  being  made,  and  this  natural  system  of  classification  must 
be  regarded  as  a  most  useful  attemi)t  to  indicate  just  such  genetic 
relationships  as  exist  among  human  beings. 

The  divisions  and  sub-divisions  thus  established  stand  as  ft>llows: 

Divisions. — Of  which  there  are  two,  the  Cryptogamia  and  Phanero- 
gamia,  the  latter  being  now  often  called  Spermatophyta,  as  the  pro- 
duction of  seeds  is  regarded  as  their  most  important  characteristic. 

Sub-divisions. — Leaving  out  of  consideration  the  divisions  of  the 
Cryptogamia,  we  find  the  Phanerogamia  divided  with  two  sub-divisions, 
the  Gymnospcrmae  and  the  Angiosperniae,  the  latter  the  higher. 

Classes. — Leaving  out  of  account  the  Gymnospermae,  the  Angio- 
spermae  are  divided  into  two  classes,  the  Monocotyledons  and  the 
Dicotyledons. 

Series. — The  Dicotyledons  are  divided  into  three  series,  the  Thal- 
amiflorae,  Disciflorae  and  Calycifiorae. 

Cohorts. — Each  of  the  series  named  above  is  divided  into  a  num])er  of 
Cohorts,  or  orders.  Thus  the  Thalamiflorae  have  G  cohorts,  namely, 
Ranales,  Parietalcs,  Polygalinae,  CaryophylUneae,  Guttifcrales,  and 
Mai  vales. 

Families. — Each  cohort  consists  of  a  number  of  Fatnilics,  of  which 
there  are  about  3{)()  among  flowering  plants,  the  Ranunculaceae  or 
Buttercup  Eamily  and  the  Compositae  or  Daisy  Eamily  being  exam})les. 

Sub-families  and  Tribes. — Families,  if  large  or  heterogeneous,  are 
often  divided  into  Tribes,  or  into  Sub-families,  the  latter  then  divided 
into  Tribes.  Thus,  the  Ranunculaceae  contain  5,  the  Compositae  13 
tribes. 

Genera. — Families,  either  directly  or  through  their  tribes,  are  divided 
into  genera,  of  which  the  most  modern  authorities  recognize  between 
8()()()  and  9(K)()  in  all  the  families  of  flowering  ])lants.  The  genera  are 
very  irregularly  distributed  among  the  families.  Thus,  the  family 
Columelliaceae  contains  but  one  genus,  Coluinellia,\\hi\e  the  CoDiposiiae 
is  made  up  of  some  SOO  of  them. 

Species. — Genera,  either  directly  or  through  a  number  of  Sub-genera, 
are  made  u])  of  species,  of  which  there  are  })robal)ly  not  far  from  2r)(),()()() 
now  described  among  flowering  plants.  These  are  very  irregularly 
distributed  among  the  genera,  many  of  the  latter  containing  but  one 
species,  while  others  contain  hundreds.  Solanuui.  pi-obablx'  tlic  largest 
genus,  has  been  credited  with  as  many  as  1200  species. 


220  BOTANICAL  CLASSIFICATION  AND  ANALYSIS 

A  species  is  considered  as  an  nitimate  individual  kind  of  plant,  like 
the  Red  Maple,  the  ordinary  medicinal  Wild  Cherry,  or  the  Two-leaved 
Pink  Ladyslipper. 

Varieties. — Varieties  frequently  exist  among  the  individuals  of  a 
species.  It  is  practically  impossible  to  establish  rules  for  determining 
whether  two  closely  related  forms  are  two  species  or  two  varieties  of 
one  species,  and  there  is  hardly  a  point  upon  which  our  botanists  are 
more  at  a  disagreement  than  in  estimating  these  cases.  It  may  be  said 
that  a  variety  is  a  form  of  a  species  which  depends  either  upon  a  natural 
tendency  to  vary,  or  upon  modifications  brought  about  by  difl'erent 
climatic  conditions  or  other  environment,  but  which,  in  either  case,  is 
not  permanently  fixed,  its  descendants  being  liable  under  various  con- 
ditions to  reassume  the  characters  of  the  parent.  The  characters  of  a 
species  are,  upon  the  other  hand,  supposed  to  have  become  permanently 
fixed.  It  may,  of  course,  vary,  but  there  is  no  special  tendency  for  it 
to  vary  in  the  direction  of  the  ancestral  form  more  than  from  it,  in  a 
new  direction. 

Forms. — Variations  which  are  not  at  all  fixed,  and  clearly  temporary 
in  their  nature,  as  the  occurrence  of  a  white  fiower  among  plants  habitu- 
ally blue-flowered,  give  rise  to  Forms.  These  are  hardly  considered 
worthy  of  names. 

Botanical  Analysis. — This  consists  in  the  determination  of  the  botani- 
cal ])osition  and  name,  if  it  have  one,  of  a  plant,  by  comparing  it  with 
published  descriptions  until  that  one  is  found  with  which  it  agrees. 
To  make  such  comparisons  individually,  and  without  system,  would 
prove  interminable  among  such  a  vast  number  of  species,  and  the  system 
of  classification  above  mentioned  is  employed  to  reduce  to  a  minimum 
the  time  and  labor  required.  The  process  is  essentially  one  of  successive 
exclusions  of  the  plant  under  study  from  more  or  less  extensive  divisions 
and  subdivisions. 

By  determining  that  our  plant  produces  flowers  and  seeds,  we  exclude 
it  from  the  Cryptogamia,  approximately  half  of  the  vegetable  kingdom. 
Another  similar  act  excludes  either  the  Angiospermae  or  Gymnospermae 
and  another,  if  it  be  an  Angiosperm,  from  either  the  Monocotyledones 
or  Dicotyledones.  As  the  process  continues,  it  becomes  somewhat  more 
complicated.  The  first  steps  may  be  positively  taken  by  deciding  a 
single  point,  but  farther  on,  in  determining  the  family,  genus,  and 
species,  groups  of  characters  have  to  be  considered  together,  and 
held  in  mind  at  the  same  time  for  comparison.  This  is  in  general  due 
to  the  fact  that  the  characters  separating  the  primary    groups    are 


BOTANICAL  ANALYSIS  221 

older  in  time,  and  tlierei'ore  more  constant  and  less  inclined  to  vary, 
while  those  characterizinjj  the  lesser  groups  are  more  recent  in  their 
origin,  and  nnicli  inclined  to  vary  in  diflerent  individuals.  They  are, 
therefore,  less  trustworthy  and  have  to  be  considered  in  connection 
with  others.  It  is  for  this  reason  that  the  most  frequented ifl'erences  of 
opinion  concerning  classification  among  botanists  relate  to  genera, 
species  and  varieties. 


CHAPTER    XX 

BOTANICAL   NOMENCLATURE 

In  naming  a  plant,  the  object  is  to  apply  a  name  which  does  not  and 
cannot  be  made  to  apply  to  any  other.  A  familiar  illustration  is  the 
name  of  the  common  Red  Maple.  In  scientific  circles  the  name  "  Red 
jNIaple"  cannot  be  regarded  as  sufficiently  exact  and  definite,  because 
in  different  localities  it  is  known  as  Soft  maple,  Swamp  maple,  White 
maple,  and  Early  maple;  while  doubtless  different  maples  are  called 
"Red"  in  different  localities. 

Scientific  accuracy,  therefore,  renders  it  indispensable  that  a  system 
of  botanical  or  scientific  names,  as  distinguishable  from  the  common, 
vulgar,  or  trivial  names,  shall  be  employed.  The  name  Acer  is,  therefore, 
applied  to  the  genus  to  which  the  maples  belong,  and  this  is  known 
as  the  generic  name  of  all  the  species  of  j\Iaple.  One  of  the  rules  of 
nomenclature  requires  that  no  other  genus  shall  bear  this  name.  In 
order  to  distinguish  the  different  species  of  Acer,  each  must  have, 
in  addition,  its  specific  name,  the  Red  jNIaple  receiving  the  specific 
name  of  Rubruni.  It  is,  therefore,  to  be  known  as  the  Rubruvi  AeeVj 
although  the  Latin  form,  with  the  generic  name  preceding,  is  employed 
thus,  Acer  ruhrum,  the  specific  name,  except  in  certain  cases,  beginning 
with  a  small  letter.  By  another  rule  of  nomenclature,  only  this  par- 
ticular Acer  may  be  called  ruhrum,  although  this  name  may  be  applied  to 
plants  in  other  genera  than  Acer.  It  is  clear  now  that  this  combination 
of  generic  and  specific  names  yields  a  complete  name,  and  this  is  called 
the  Binomial,  which  may  not  be  applied  to  any  other  plant  in  the  world, 
while  either  its  generic  or  specific  name  may  be. 

It  often  happens  that  a  plant  name  is  for  one  reason  or  another 
abandoned  by  some,  or  most,  or  even  all  botanists.  It  is  not  then 
permitted  that  it  be  given  to  another  plant,  because  it  is  liable  at  any 
time  to  be  used  again  in  its  old  application  by  other  botanists,  so  that 
we  should  then  come  to  have  two  plants  of  that  name. 

In  spite  of  the  rules  here  stated,  it  frequently  does  happen,  very 
frequently  has  happened  in  the  past,  that  a  botanist,  ignorant  or  care- 
less that  a  certain  name  has  been  used,  applies  it  to  some  other  species, 


BOTANICAL  NOMENCLATURE  223 

thus  causing  a  duplication.  In  such  a  case  the  name  Acer  rnbrum 
could  not  inform  us  with  certainty  which  species  was  referred  to  by  the 
writer  or  s])eaker.  It  might,  for  example,  he  an  Am-  niJn-inn  made  by 
Linne  in  1753  or  one  so  named  by  some  one  else  in  ISSO.  It  is  therefore 
necessary  to  add  to  the  plant-name  the  name  of  its  jnitlior,  thus,  .leer 
rubrum  Linne.  This  necessity  for  the  use  of  the  a.uthor's  name  is  semi- 
barbarous,  and  is  a  mere  monument  to  the  lack  of  system  in  plant- 
naming  which  once  existed.  With  the  perfect  systematizing  of  nomen- 
clature this  necessity  will  pass  away.  For  convenience,  it  is  customary 
to  abbreviate  the  name  of  the  author  thus,  L.  for  Linne,  Reichb.  for 
Reichenbach,  or  Benth.  for  Bentham.  The  generic  name  may  also 
be  abbreviated  in  many  cases  by  writing  only  its  first  letter,  followed 
by  a  period,  thus,  A.  rubrum  L.  This  of  course  can  only  be  done  when 
it  is  well  understood  to  what  genus  the  writer  is  referring.  For  example, 
in  the  above  cases,  where  we  have  been  speaking  only  of  Acers,  the 
abbreviation  "A."  can  be  employed  with  entire  satisfaction. 

A  name  in  parentliesis  will  sometimes  be  found  interposed  between 
the  generic  and  specific  names  thus,  Acer  (Negundo)  aceroidcs.  This 
indicates  that  the  genus  consists  of  two  or  more  sub-genera,  the  one  in 
this  case  being  Negundo.  It  is  not  customary  to  indicate  the  sub- 
genus in  this  way,  but  a  writer  often  desires  for  some  special  reason  to 
do  so. 

The  name  of  an  author  enclosed  in  parenthesis  is  often  seen  standing 
between  the  specific  name  and  that  of  the  author,  thus  Acer  aceroides 
(^Nloench)  Gray.  This  means  that  the  botanist  named  in  the  paren- 
thesis assigned  to  the  plant  its  specific  name,  but  connected  it  with 
some  other  genus,  the  later  author,  whose  name  follows  the  parenthesis, 
having  transferred  it  to  the  present  genus,  thus  creating  the  present 
binominal.  In  all  cases  where  a  plant  is  thus  transferred  to  a  different 
genus,  it  must  retain  its  original  specific  name,  unless  the  genus  to  which 
it  is  so  transferred  already  has  a  species  with  that  name,  in  which  case 
a  new  specific  name  must  be  assigned,  this  necessity  being  to  a^•oid 
binomial  duplication. 

Wlicn  the  name  of  the  author  in  parenthesis  is  not  followed  by 
another,  it  means  that  the  writer  claims  that  this  binomial  has  never 
been  printed  and  that  he  must  henceforward  be  cited  as  its  author. 

We  frequently  see  a  trinomial  used  as  the  name  of  a  jilant.  thus, 
Viola  tricolor  alba,  no  parenthesis  being  used  for  the  middle  iianic. 
This  indicates  that  the  species  Jlola  tricolor  sometimes  exhii)its  a  form 
possessing  white  flowers,  and  that  this  form  is  regarded  as  a  variety  of 


224  BOTANICAL  NOMENCLATURE 

the  species.  The  name  alha  is  in  this  case  called  the  varietal  name. 
Another  way  of  writing  it,  but  which  has  not  the  sanction  of  botanists, 
is  "Viola  tricolor,  var.  alba." 

The  use  of  capitals  and  italics  in  printing  botanical  names  is  not, 
except  in  special  cases,  of  botanical  significance  or  authority,  though 
attempts  have  been  made  to  so  treat  it.  Literature  and  individual 
taste  supply  the  rules  for  this  usage.  This  statement  does  not,  how- 
ever, apply  in  the  case  of  the  initial  of  the  generic  name  or  of  the  name 
of  the  author. 

It  has  been  shown  above  how  two  plants  may  come  to  have  the  same 
name  assigned  to  them.  In  even  a  greater  number  of  instances  have 
several  different  names  come  to  be  applied  to  the  same  plant.  The 
extent  to  which  this  has  occurred  may  be  realized  from  the  fact  that 
more  than  eight  hundred  thousand  names  exist  for  the  two  hundred 
and  fifty  thousand  known  flowering  plants,  this  being  an  average  of 
more  than  three  names  for  each  plant.  Since  only  one  name  can  be 
recognized  for  a  plant  and  only  one  plant  for  a  name,  it  follows  that 
all  others  must  be  regarded  as  synonyms  and  should  not  be  used. 
Until  a  comparatively  recent  period  very  autocratic  methods  have 
ruled  in  the  selection  and  application  of  names  under  these  circum- 
stances. Each  country  has  had  but  a  few,  or  even  but  one  botanist 
who  assumed  authority,  and  these  have,  in  most  instances,  acted 
irregularly  and  inconsistently  in  selecting  and  applying  their  names. 
Now,  however,  most  botanists  recognize  the  importance  of  having  some 
uniform  custom,  based  upon  sound  principles,  and  the  attempts  in  this 
direction  ^re  likely  to  result  in  great  improvement. 

The  fuxidamental  rule  of  nomenclature  is  that  the  first  names,  generic, 
specific,  and  binomial,  ever  given  to  a  plant,  beginning  with  the  year 
1753,  sh?ll  be  permanent,  provided  that  they  do  not  involve  errors. 
Such  errors  may  be  literary  or  botanical.  Literary  errors  may  consist 
in  wrong  spelling  or  inflection,  or  in  a  composite  derivation,  part  of 
the  name  being  taken  from  the  Greek  and  part  from  the  Latin.  Such 
errors  do  not  justify  the  substitution  of  another  name,  but  only  a  correc- 
tion, with  as  little  change  as  possible.  Botanical  errors  justifying  the 
substitution  of  a  new  name  are  numerous  and  varied.  The  most 
common  is  the  reference  of  the  plant  to  a  wrong  genus,  as  calling  a 
Ruhus  a  Rosa.  Whoever  discovers  such  a  mistake  is  required  to  refer 
the  species  to  its  proper  genus,  but  its  specific  name  must  if  possible 
remain  unchanged.  The  name  of  the  author  of  the  specific  name  then 
goes  in  parenthesis,  as  already  explained.    Not  ah  changes  of  this  sort 


BO  TA  NIC  A  L  NOMENCLA  TURK  225 

indicate  actual  errors.  The  lines  of  distinction  Ix'twccn  two  f,fcncra 
are  often  very  ari)itrary,  the  different  ()i)inions  of  different  botanists 
being  apparently  equally  well  founded.  One  botanist  will  thus  regard 
as  of  one  genus  plants  which  another  divides  among  two  or  more  genera. 

Another  very  common  error  in  the  past  was  that  of  assigning  to  a 
genus  a  name  which  had  already  been  applied  to  another.  This,  of 
course,  necessitates  a  re-naming  of  the  genus,  all  the  specific  names 
remaining  unchanged  and  their  autliors  cited  in  ])arenthesis  as  already 
explained. 

Errors  in  specific  names  have  occurred  most  frequently  through  the 
re-naming  of  a  species  which  has  already  been  published  under  a  difierent 
name.  In  such  cases,  when  the  error  is  discovered,  the  name  last  given 
must  fall.  A  difference  of  opinion  has  existed  as  to  whether  such  a 
discarded  name  should  be  permitted  to  be  afterward  taken  up  and 
applied  to  a  newly  discovered  plant.  If  the  error  in  the  first  use  of  the 
name  were  beyond  question,  no  harm  would  result  from  so  doing,  but 
such  is  not  the  case.  In  numerous  cases  botanists  have  disagreed  as 
to  the  specific  identity  of  two  plants.  One  regards  one  of  the  plants 
as  a  mere  accidental  or  temporary  state  of  the  other  and  discards  its 
specific  name.  If,  now,  the  discarded  name  be  applied  to  some  other 
species  of  that  genus,  there  is  danger  that  at  any  time  the  original 
opinion  may  be  revived  concerning  the  previous  application  of  that 
name.  This  having  in  the  meantime  been  applied  to  another  si)ecies, 
we  have  the  same  name  applied  to  two  species.  For  this  reason  conser- 
vative botanists  hold  that  just  as  a  generic  name  once  discarded  may 
never  be  given  to  another  genus,  so  a  specific  name,  once  dropped, 
may  never  be  applied  to  any  other  species  in  the  same  genus.  '  This 
constitutes  the  important  rule  often  referred  to,  as  in  the  cxjjression, 
"Once  a  synonym  (or  homonym)  always  a  synonym." 

The  whole  subject  of  nomenclature  and  the  rules  which  have  been 
formulated  for  it  are  very  extended  and  c()mi)licated,  but  the  most 
important  ])rinciples  upon  wliicli  the  rules  are  based  have  here  been 
explained. 


15 


CHAPTER    XXI 

THE  COLLECTION  AND  PRESERVATION  OF  BOTANICAL  SPECIMENS 

The  study  of  botany  cannot  be  properly  pursued  without  the  pres- 
ervation of  specimens.  The  mistake  is  very  general  of  assuming  that 
such  material  is  required  only  in  case  of  the  making  of  a  permanent 
herbarium.  It  is  necessary  besides  as  a  temporary  expedient  in  the 
thorough  study  of  plants.  A  plant  is  not  studied  until  all  its  parts 
have  been  examined.  As  the  mature  fruit  is  rarely  present  with  the 
flower,  and  as  the  stem,  leaves  and  underground  portions  are  liable  to 
present  different  characters  at  different  seasons,  it  becomes  necessary 
to  make  several  collections  from  the  same  plant  and  to  preserve  them 
to  be  studied  together.  There  is,  moreover,  a  waste  of  time  involved 
in  using  the  summer  season  for  dissection  and  study,  when  the  attention 
should  be  directed  to  field-work. 

Specimens  may  be  preserved  in  alcohol  or  in  formaldehyde  or  other 
solution,  or  they  may  be  preserved  by  drying.  The  latter  method  is 
usually  employed  and  is  the  more  generally  useful,  although  it  possesses 
certain  disadvantages  which  will  be  referred  to  further  on. 

Alcoholic  specimens  are  made  by  simply  immersing  the  material  In 
alcohol  and  sealing  perfecth'.  Very  fleshy  specimens  may  require  a 
change  of  alcohol  after  a  time.  An  improvement  on  this  method  is  to 
immerse  them  in  50  per  cent,  alcohol  for  a  few  days,  then  transfer  them 
to  75  per  cent,  alcohol  and  later  to  that  of  full  strength  (95  per  cent.). 
Alcohol  is  liable  to  remove  coloring  matters  and  many  other  substances, 
as  well  as  to  extract  the  natural  water,  thus  giving  to  the  specimens  a 
shriveled  or  wrinkled  appearance.  The  use  of  a  formaldehyde  solution 
obviates  both  of  these  difficulties,  even  the  most  delicate  colors  being 
in  most  cases  perfectly  preserved.  The  strength  of  the  solution  ranges 
from  3  to  9  per  cent.,  ordinary  water  being  employed  as  a  vehicle.  In 
the  case  of  fleshy  fruits  and  some  other  substances,  it  is  found  necessary 
to  pour  off  the  first  solution  and  apply  a  fresh  one  after  a  few  days,  and 
this  renewal  may  be  called  for  from  time  to  time  as  the  specimens  show 
signs  of  deterioration.  Under  the  very  best  of  conditions,  it  must  be 
expected  that  some  changes  will  occur  in  the  appearance  of  specimens 
preserved  in  solution,  and  the  same  is  true  of  those  prepared  by  drying, 


THE  RECORD  HOOK  Til 

SO  that  it  hfcomcs  necessary  to  take  careful  notes  re<^ar(]in<;-  ])lants  at 
the  time  of  their  collection. 

The  Record  Book.— The  record  is  to  include  the  colle<tion  number  of 
the  specimen,  which  is  also  to  })e  attached  to  the  specimen  at  the  same 
time,  the  date,  locality,  altitude,  habitat,  habit  of  the  ])lant,  color  and 
any  other  facts  not  likely  to  be  readily  reco<i;ni/e(l  in  the  dried  specimen. 


FieU  No. 
256 

O 

Bolivian  Flora. 

!     « 

:         & 

:        *i 

1    1 

Bang  Collection. 

Field  No. 

i 

1      j 

Ci 

250 

G 

i 

Bolirian  Flora. 

H-"           J 

Bang  Collection. 

!        I 

O       : 
: 

Field  No. 

260 

o  1" 

i 

o 

Bolivian  Flora. 

5'    Q 

^ 

Bang  Collection. 

_=  ■ 

a 

The  l)est  form  of  note-book  is  one  containing  lOO  pages  like  that  here 
figured,  a  convenient  size  for  which  is  4  x  7  inches  and  printed  on  \ery 
strong  and  tough  paper,  such  as  cartridge-pai)er.  The  numbers  borne 
on  these  pages  are  to  be  printed  by  machine,  so  as  to  avoid  all  pos- 
sible form  of  error.  Through  the  holes  in  the  tags  at  the  bottom  of  the 
page  strings  are  to  be  tied  and  the  tags  are  to  be  firmly  attached  to  the 
specimens.  When  the  specimen  is  studied  later  there  can  thus  be  no 
possible  question  as  to  the  specimen  to  which  the  notes  refer.  When 
the  specimen  is  finally  mounted  in  the  herbarium,  the  remainder  of  the 
page  should  be  torn  out  and  glued  to  the  sheet,  the  tag  still  remaining 
attached  to  the  plant  as  indisi)utable  evidence  of  identity.  With 
great  care,  a  similar  assurance  is  i)ossible  without  these  elaborate 
provisions. 

Besides  the  notes  referred  to  aboxe,  it  may  Ix-  necessary  to  note  the 
dioecious  character  of  a  plant,  in  which  case  that  of  the  other  sex  must 
also  be  sought.  This  should  be  given  the  same  number,  followed  by 
the  proper  sexual  sign  or  by  the  letter  a  or  b.  If  the  leaves  are  not  yet 
developed  when  the  flowers  appear,  as  is  frecjueutly  the  case  with  early 


228  THE  COLLECTION  OF  BOTANICAL  SPECIMENS 

spring  flowers,  an  estimate  should  be  made  of  the  time  when  the  leaves 
will  probably  be  ready  for  collection  and  the  number  of  the  plant 
entered  in  an  engagement  calendar  under  the  pro])er  date  at  which  the 
place  should  be  again  visited.  The  same  thing  is  true  in  case  the  fruit 
is  not  ready  at  the  time  of  .the  collection  of  the  flowers.  In  these  cases 
it  is  best  to  attach  a  tag  to  the  living  plant  at  the  time  of  the  first 
collection  to  avoid  all  possibility  of  confusing  two  species  in  the  final 
complete  collections. 

Selecting  the  Specimens. — This  matter  of  representing  all  parts  of  the 
plant  and  the  same  parts  at  different  seasons  is  of  special  importance 
in  case  of  pharmaceutical  studies.  Even  the  winter-buds  and  the 
underground  portions  in  the  winter  season  should  be  secured.  One  of  the 
most  important  points  is  to  secure  the  root-leaves  of  ordinary  herbaceous 
plants,  as  well  as  the  peculiar  leaves  of  trees  and  shrubs  which  often 
grow  upon  root-suckers  or  upon  young  specimens.  It  is  also  wise  to 
cause  the  germination  of  seeds  and  to  preserve  the  seedlings  with  the 
remainder  of  the  specimen.  Pharmaceutical  specimens  moreover  should 
represent  the  bark  and  the  wood  and  these  may  with  profit  be  taken 
separately  from  root,  stem  and  branch. 

Ordinary  herbarium  specimens,  when  finally  completed,  skould 
not  exceed  sixteen  inches  in  extreme  length  by  ten  inches  in  width. 
Even  specimens  of  three  or  four  feet  in  length  may  be  easily  reduced 
to  this  size  by  kinking  and  folding  them  at  the  proper  points  without 
entirely  separating  any  part.  Underground  port  ons,  when  not  too 
large,  should  remain  attached.  Inconveniently  thick  portions,  such 
as  tubers  or  fruits,  may  be  split  and  one  or  both  parts  preser^'ed,  or  the 
centre  may  be  cut  out  so  as  to  reduce  the  thickness.  In  the  case  of 
large  specimens,  it  will  frequently  be  found  necessary  to  remove  a 
portion  of  the  leaves.  This  should  be  very  judiciously  done,  those 
retained  being  left  at  difi'erent  points  upon  the  specimen  so  as  to  show 
the  successive  modifications,  and  portions  of  the  petioles  should  be 
left  so  as  to  indicate  their  position.  In  case  of  large  plants,  such  as 
shrubs  and  trees,  where  only  a  branch  can  be  preserved,  it  is  impor- 
tant to  select  this  branch  from  a  part  where  growth  has  been  free 
and  unrestricted  and  a  natural  symmetry  attained.  With  each 
specimen,  a  few  loose  flowers  and  buds  should  be  preserved  for 
dissection  i)urposes. 

Preserving  the  Specimen. — Specimens  thus  taken  should  be  at  once 
transferred  to  a  portfolio  carried  into  the  field.  Various  forms  of 
portfolios  are  for  sale  by  botanical  supply  houses.      They  may  be 


PRESERVING   THE  SPECIMENS  229 

made  of  cardboai'd,  wood-ljoard,  wooden  lattiee  work  or  wire  frames,  and 
they  should  be  earried  iu  a  strong-  ])air  of  strai)s,  simihir  to  the  ordinary 
shawl-.straj).  The  portfoHo  should  contain  a  number  of  double  sheets 
of  paper  of  about  11  x  17  inches.  Xothinji;  better  can  be  ol)tained  than 
single  i)ages  of  an  ordinary  New  York  daily  newsi)aper  once  folded. 
Within  this  fold  the  specimen,  with  tag  attached,  is  to  be  laid,  its  leaves 
and  flowers  as  straight  as  can  be,  one  or  more  of  each  turned  with  the 
face,  and  others  with  the  backs  uppermost.  While  being  carried  in  the 
portfolio,  they  should  be  subjected  to  strong  pressure  to  i)revent 
wrinkling,  and  none  of  the  parts  must  be  allowed  to  project  beyond  the 
edges  of  the  paper. 

Within  twenty-four,  and  nnich  better  within  six  or  eight  hours  of 
the  time  of  collection,  the  folds,  with  specimens  contained,  are  to  be 
transferred  to  the  dryers.  At  this  time,  each  specimen  should  be  gone 
over,  its  leaves  and  flowers  perfectly  straightened  out  and  arranged 
in  the  position  desired  when  dry.  It  is  often  desirable  to  introduce 
several  thicknesses  of  bibulous  paper  inside  of  the  specimen  sheets,  so 
as  to  make  the  entire  thickness  correspond  with  that  of  any  excessively 
thick  portion  of  the  specimen,  such  as  a  large  root,  fruit  or  tuber. 

The  drjers  are  to  consist  of  some  thick  bibulous  paper.  When  little 
collecting  is  to  be  done,  blotting  paper  is  desirable,  but  when  collecting  is 
upon  an  extensive  scale,  this  is  far  too  expensive  and  })erishable.  Various 
forms  of  dryers  of  excellent  quality  are  for  sale  by  the  botanical  supply 
houses,  but,  in  drying  on  a  large  scale,  it  has  been  found  possible  to 
effect  considerable  saving  by  improvising  them  out  of  some  suitable 
material.  The  author  has  found  the  best  method  to  be  to  obtain  rolls 
of  thick,  gray  house-sheathing  paper,  30  inches  in  length.  This  may 
then  be  cut  into  12-inch  lengths,  and  folded  to  a  size  of  12  x  IS  inches. 
When  the  amount  of  the  material  drying  is  large,  it  is  better  cut  in 
24-inch  lengths  and  folded  to  24  x  18  inches.  Dryers  of  this  size  will 
then  accommodate  two  specimen  sheets  lying  side  by  side.  There  are 
so  many  varieties  and  qualities  of  house-sheathing  on  the  market,  that 
careful  selection  is  necessary.  For  plant-dryers  it  should  be  free  from 
mineral  and  coloring  matters,  tar  and  sizing,  and  its  quality  should  be 
tested  by  its  ability  to  take  uj)  moisture  readily.  As  a  general  state- 
ment,* it  may  be  said  that  that  grade  ordinarily  denominated  "poor"  by 
builders  should  be  sought.  The  numl)er  of  dryers  between  two  layers 
of  s])ecimens  should  be  determined  by  the  auKHUit  of  herbage  possessed 
by  the  latter,  by  the  condition  of  the  weather  and  climate,  the  facilities 
for  frecjuent  changes  of  dryers  and  other  similar  conditions.     In  hot, 


230  THE  COLLECTION  OF  BOTANICAL  SPECIMENS 

dry  weather  only  one  folded  dryer  is  required  for  ordinary  herbaceous 
plants  of  temperate  climates,  provided  the  dryers  are  changed  twice 
or  even  thrice  a  day.  In  bad  weather,  or  with  thick,  water-laden  speci- 
mens, or  when  the  plants  must  remain  more  than  twenty-four  hours  in 
the  dryers  without  change,-  four  folded  dryers  are  required.  By  using 
a  large  number  of  dryers  in  the  best  of  weather,  it  is  frequently  possible 
to  dry  ordinary  specimens  with  but  one  change  of  dryers ;  or  even  without 
change,  to  secure  specimens  of  the  first  quality. 

Powerful  pressure  should  next  be  applied.  Weights,  screws  or  levers 
may  be  employed  for  this  purpose,  but  no  other  method  is  equal  to 
the  use  of  straps.  These  should  be  made  of  the  heaviest  and  best 
leather  obtainable,  should  be  li  or  1^  inches  in  wddth  and  provided 
with  a  large  strong  buckle,  the  holes  not  more  than  two  inches  apart 
and  punched  to  within  two  feet  of  the  buckle.  The  length  of  the  straps 
should  be  proportional  to  the  size  of  the  bundle  drying.  For  extensive 
collecting,  straps  of  8  feet  are  required.  The  straps  should  be  laid  only 
a  few  inches  apart  and  the  bundle  laid  upon  them  so  that  the  buckle 
barely  projects  from  under  the  edge.  The  straps  should  be  drawn 
firmly  into  place  without  drawing  the  buckles  from  their  place.  The 
operator  now  stands  upon  the  bundle  and  stamps  it  firmly  at  all  points, 
so  that  no  parts  of  the  specimens  are  left  without  a  firm  application 
of  the  dryers.  The  straps  are  then  drawn  as  tightly  as  possible  and 
secured.  A  strong  man  can  thus  secure  pressure  of  500  or  600  pounds, 
all  of  which  is  required  for  a  pile  of  dryers  two  feet  or  more  in  height. 
Even  then  it  will  be  found,  after  the  lapse  of  two  or  three  hours,  that 
the  pressure  has  become  almost  completely  relaxed,  owing  to  the  wilting 
and  shrinking  of  the  specimens,  and  the  straps  must  be  tightened. 
The  pile  should  now  be  stood  upon  the  end  on  a  dry  stone  or  wooden 
support,  a  pole  frame  being  best.  The  flat  side  should  be  exposed  to  the 
sun,  or  quite  as  good,  to  the  heat  of  the  kitchen  range.  When  possible, 
the  dryers  should  be  changed  twice  a  day  for  the  first  day  or  two.  The 
dryers  into  which  the  sheets  are  to  be  transferred  should  be  perfectly  dry 
and  if  possible  hot  from  the  sun.  When  it  is  not  possible  to  expose  them 
to  the  sun  just  previous  to  making  a  change  in  the  morning,  they  should 
be  wrapped  tightly  in  a  rubber  cloth  when  brought  in  from  the  sunshine 
of  the  previous  afternoon,  as  dryers  not  thus  protected  will  absorb  a 
considerable  amount  of  moisture  during  the  night.  It  is  to  be  con- 
sidered that  the  first  hour  in  perfectly  dry,  hot  dryers  contributes  quite 
as  much  to  the  beauty  of  the  specimens  as  the  succeeding  five  hours. 

In  making  the  change,  the  specimen  sheets  are  to  be  transferred  to 


MOUNTING  THE  SPECIMENS  ^31 

the  fresh  drj'ers  without  opening.  Under  the  ahove  treatment,  in  hot 
and  very  dry  weather,  most  specimens  will  he  dried  i)erf'eetly  in  ironi 
three  to  four  days.  Upon  the  tahlelands  of  Mexico  and  similar  localities 
only  half  of  this  time  is  required.  Many  plants,  such  as  orchids  or 
cactuses,  may  require  all  summer  for  drying  and  are  even  frequently 
worn  out  in  the  ])rocess  of  changing  before  they  become  dry.  Such 
plants  may  be  dipped  for  an  instant  in  boiling  water  l)efore  being  dried. 
This  process,  while  it  greatly  expedites  drying,  is  apt  to  make  the 
specimen  turn  black. 

Great  judgment  is  required  to  avoid  regarding  a  specimen  as  dry 
before  it  really  is  so.  The  test  is  to  see  that  any  part  will  snap  off  in 
attempting  to  bend  it.  Even  after  the  specimens  are  perfectly  dry  they 
should  not  be  sealed  up  at  once,  as  they  are  liable  to  undergo  a  sweating 
process  during  the  succeeding  day  or  two.  They  should  be  tied  tightly 
in  bundles  and  these  bundles  exposed  to  the  sun  for  an  hour  or  two  on 
several  successive  days,  after  which  they  may  be  sealed  up,  a  good 
method  being  to  wrap  them  tightly  in  waxed  paper,  this  protected  by 
hea\ier  ])a])er,  for  transportation  through  a  moist  climate. 

Poisoning  the  Specimen. — ^^arious  methods  have  been  resorted  to 
for  poisoning  specimens  so  as  to  make  them  proof  against  the  attacks 
of  the  small  insects  which  infest  the  herbarium,  but  in  no  case  have  the 
results  proved  permanent.  Arsenical  and  mercural  solutions  have  been 
most  employed.  Upon  the  whole,  a  saturated  alcoholic  solution  of 
corrosive  sublimate  is  the  most  satisfactory  poisoning  agent.  Theo- 
retically, the  corrosive  sublimate  soon  becomes  converted  into  calomel, 
but  in  practice  its  effects,  if  it  be  thoroughly  applied,  last  for  a  great 
nian.\-  years.  It  may  be  poured  upon  the  specimen,  applied  with  a  brush, 
hea\  ily  sprayed  from  an  atomizer,  or  the  specimen  dipped  into  it.  It 
is  to  be  treated  as  a  very  dangerous  poison,  not  only  internally,  but 
highly  irritating  to  eyes,  nose,  and  lungs  and  capable  of  poisoning  by 
inhalation  of  the  spray. 

When  insects  are  found  attacking  mounted  si)ecimens,  the  latter 
should  be  enclosed  in  a  tight  case  and  subjected  for  some  hours  to  the 
vai)or  of  carbon  disuli)hide. 

Mounting  the  Specimens. — For  permanent  mounting  in  the  herbarium, 
sheets  of  standard  size  (Kiixllf  inches)  should  be  used  and  the 
l)ai)er  should  be  white  and  very  lieaAy.  ^Fuch  ])aper  now  made  of 
wood-pulj)  (piickly  becomes  yellow  or  brown,  and  scrupulous  care  to 
avoid  this  quality  should  be  taken.  The  specimens  are  to  be  secured 
by  the  use  of  white  glue  applied  over  the  entire  surface  and  the  stems 


232  THE  COLLECTION  OF  BOTANICAL  SPECIMENS 

and  branchlets  should  also  be  strapped  down  with  strips  of  gummed 
linen.  Before  attaching  a  specimen  to  the  sheet,  it  should  be  carefully 
examined  to  see  that  it  exhibits  both  surfaces  of  the  leaves,  as  well  as 
both  the  inner  and  outer  surfaces  of  the  flowers.  Finally,  an  appropriate 
label  is  to  be  gummed  to  a  convenient  part  of  the  sheet,  preferably  to 
the  lower  right-hand  corner. 

Wood  specimens  and  other  parts  which  cannot  be  attached  to  the 
sheets  may  be  preserved  in  suitable  boxes  or  cabinets,  according  to 
the  taste  and  means  of  the  collector.  In  all  such  cases,  careful  reference 
should  be  made  upon  the  label  of  each  part  of  a  specimen  to  the  existence 
of  the  other  parts  elsewhere. 

Collecting  Specimens  for  Immediate  Examination  in  the  Fresh  State. — 
For  this  purpose,  various  forms  of  tin  case,  commonly  known  as  vascu- 
lums,  are  provided.  In  these  cases,  specimens  placed  without  free 
access  of  air  and  light  and  without  the  addition  of  anything  more  than 
their  natural  moisture,  may  be  preserved  perfectly  for  many  days.  In 
the  absence  of  proper  vasculum,  any  tin  pail  or  tin  })ox  with  a  tightly 
fitting  cover  may  be  used.  The  author  has  found  it  very  convenient 
to  carry  with  him  a  square  yard  of  thin  rubber  cloth,  which  may  be 
folded  tightly  and  carried  in  the  pocket  without  any  inconvenience, 
and  used  when  occasion  requires. 


INDEX 


Numbers  in  parenthesis  indicate  figure  numbers;  outside  of  parenthesis,  pages. 


Abortion  (38),  38 

of  septa  (230),  106 

of  theca,  68 
Abruptly  acuminate  (508,  etc.),  183 
Absinthium,  al<;ene  of  (76) 
Absorbing  roots,  160 
Acacia  leaf  (563) 

phyllode  (562) 
Acaulescent,  164 
Accessory  fruit,  103 

parts,  103 
Accrescent,  61 

parts,  103 
Accumbent  cotyledons  (413),  125 
Aceroso  leaf  (492),  179 
Achenium  (74-80,  342),  121 
Achillaea  leaf  (556) 
Achlamydcous,  and  symbol  for,  33 

ovules,  69 
Aconite  flower  (108) 
Acorus  inflorescence  (586) 

rhizome  (452) 

seed  (382) 
Acropetal  anthotaxy  (582,  etc.),  201 
Active  period  in  flowers,  93 
Aculeate  stem  (436),  165 
Acuminate  (511),  182 
Acute,  183 
Acyclic  flowers,  43 
Adelphism,  66 
Adenium  flower  (55) 
Adherent  calyx  (56),  44 
Adhesion  (54-57),  43,  51 
Adnate  anther  (126),  62 

disk  (253,  266),  73 

leaf  (477),  176 

stii)ulcs,  174 
Adnation  (54-57),  43 
Adonis  flower  (17) 
Adventitious  bud,  169 

roots,  160 
Aerial  roots,  160 

stems,  162 
Aeschynomene  fruit  (351),  124 
Aesculus  leaf  (547) 
Aestivation  (120-125),  59 
Aeterio  (304-305),  126 
Affinities,  19 


Agarics,  210 

Agglutination,  43 

Aggregate  fruit,  105 

Agricultural  botany,  its  departments,  19 

Agrimonia  leaf  (557) 


Agrimony  leaf  (557) 
Agrostology,  19 
Ailanthus  leaf  (508) 
Akebia  seed  (394) 
Akene  (74-80,  344),  121 
Ala  (110),  69 
Albumin,  128,  132 
Albuminous  seeds,  128 
Alburnum,  144 
Alchemilla  ovary  (179) 
Alder  inflorescence  (15) 
Algae,  211 

Allophylus  disk  (261) 
Alnus  inflorescence  (15) 
I  Aloe  stamen  (168) 
Alternate  leaves  (571),  196 
Alternation    of    generations,    in    crypto- 
gams, 207 

of  position,  law  of,  41 
Ambrosia  root  (439) 
Anient  (8,  11,  15),  202 
Ampelopsis  disk  (459),  166 
Amphitroi)ous,  81 
Amplexicaul  leaf  (479),  176 
Analogies,  19 
Analogues,  19 

Analysis  of  flower,  chai)ter  on,  86 
Anatomy  defined,  17 

gross  and  mimite,  18 
AnatrojKJUs  ovules  (242),  81 
Androecium,  chapter  on,  62 
Anemophilous  flowers,  90 

cross-pollination  in,  90 
Angiospermae,  219 
Angiospermous  gynaecia,  70 
Angularly  ovate,  181 
Annual  leaves,  175 

rings,  144 

roots,  158 

stems,  161 
Annular  rhizomes,  164 

stigma  (210-215),  74 
Antennaria  leaf  (503) 
Anteposition,  42 
Anterior  side  of  flower,  41 


234 


INDEX 


Anther  (12),  31 

attachment  of  (126-133),  62 
construction  of,  62 
cross-section  of  (14) 
dehiscence  of,  65 
foi'ms  of,  62,  64 
Antheridia,  213 
Antheridiuin  of  moss,  213 
Anthcrozoids,  100,  209 
Anthocarp,  105 

Anthodium  (343,  587),  122,  203 
Anthology,  19 

chapter  on,  23 
Anthophore  (246),  82 
Anthotaxy,  chapter  on  (576-589),  199 
Antidromy,  198 

Ants  Hving  in  inflated  leaf  (568),  195 
Apetalous,  33 
Apex  of  leaf  for  cUmbing  (567),  194 

forms  of  (506-515),  182 
Apical  placentae  (235,  237),  77 
Apiculate  (517),  183 
Apocarpous  fruit,  105 

pistil  (219,  etc.),  70 
Apocynaceae,  stigmas  in  (210,  etc.) 
Apothecia,  213 
Apparatus  for  dissecting,  86 
Appendages  to  androecium,  67 
perigone,  57 
seed  (384,  etc.),  131 
stigma,  74 
Apple  (308),  119 
Appressed  teeth  (531),  187 
Arborescent  stem,  165 
Archegonium,  213 

of  moss  (601),  213 
Arctostaphylos  anther  (145) 
Argenteous,  177 
Aril,  false,  129 
true,  129 
Arillode  (381),  129 
Arillus  (375),  129 
Arista  (78),  58 
Aristolochia  flower  (106) 
Arnica,  akene  of  (79) 
Asarum  anther  (170) 

leaf  (495) 
Ascending  anthotaxy  (582,  etc.),  201 
ovule  (238),  78 
radicle,  133 
stem,  165 
Asci,  213 

Asclepias  flower  (150,  154) 
fruit  (349) 
inflorescence  (579) 
poHination  in  (276) 
poUinium  (135) 
Ash-fruit  (339) 
Asparagus  stem  (457),  167 
Aspidium,  216 
A.ssimilation,  17 
Aster  leaf  (521) 

Novae-angliae  leaf  (479) 
Astragalus,  ovary  of  (220) 
Astronium  ovary  (178) 


Asymmetry  in  androecium,  67 
Atrojwus  ovule  (241),  81 
Attachment  of  anther  (126-133) 

transportation   of  fruit    (297,   etc.), 
109 
Attenuate  apex,  183 
Attracting  insects,  provisions  for,  91 
Auricle  (113,  153),  57 
Auriculate  (521),  184 
Author-name,  223 
Awl-shaped  (499) 
Awn  (78),  58 
Awns  (295) 
Axil  of  leaf  (1) 
Axile  embryo  (402,  403),  133 

placentae  (221,  etc.),  76 
Axillary  placentae  (221,  etc.),  76,  77 
Ayenia  flower  (90) 


B 


Bacteria,  210 

Barbarea  leaf  (559) 

Bark,  color  markings  of,  152 

defined,  150 

fracture  of,  151 

importance  in  pharmacognosy,  150 

inner  surface,  152 

layers  of  the,  150 

nature  of,  150 

outer  surface  of,  151 

ridges  and  furrows  in  (426),  152 

section  markings  of,  151 

wrinkled  (425),  152 
Barks,  how  to  study,  150 
Basal  placentae  (331),  77 

style  (179) 
Base  of  leaf,  forms  of  (516-523),  183 

relation  to  petiole,  176 

relation  to  plant  stem  (477-483),  176 
Basinerved  (528),  186 
Basipetal  anthotaxy,  200 
Bast  bundles  of  root,  142 

fibers,  142 
Bean,  ovary  of  (219) 

seed  (395) 
Beech  nut  (346) 
Befladonna  fruit  (310) 
Berberis,  metamorphosis  in  (61) 
Berry  (281-310,  etc.),  118 
Bertholetia  fruit  (324) 
Betula  leaf  (498) 
Bicollateral  bundle,  147 
Bicuculla  flower  (27) 

inflorescence  (580) 
Bidens  fruit  (300) 
Biennial  roots,  158 

stems,  161 
Bifurcating  branching  (435),  156 
liijugate,  192 
]iiiai)iatc  corolla  (111),  56 
Binomial,  222 
Biology  defined,  17 
Bi-pinnate  (563),  192 


INDEX 


235 


Bird-foot  \iolct  loaf  (553) 
Biternate  (552),  192 
Blackberry  (305) 
Black  walnut  fruit  (345) 
Bladder-wrack,  211 
Bladdery  inflated  leaf  (564) 
Blunt  (515),  1S3 
Body  of  ovule  (241,  etc.) 
Bonibax  style  (183) 
Boneset  leaf  (476) 
Borage,  ovary  (176) 
Borago  torus  (250) 
Bork,  140 

Botanical  analvsis,   nature  and   method 
of,  218 
chapter  on,  218 

classification,  chapter  on,  218 
Botany  defined,  18 
Botryosc  anthotaxy,  202 
Brace  roots,  160 
Bracts,  35,  195 
Branches,  abnormal  position  of,  154 

of  root,  origin  of,  153 

of  stem,  arrangement  of,  153 
origin  of,  153 
Branching,  diagram  explaining  (42) 
Brazil  nut  fruit  (324) 
Brunnichia  ovules  (240) 
Bryophyta,  213 
Bud  bulbs  (464),  168 

scales,  modified  leaves  (7,  etc.),  27 

the  (1,  4) 
Buds,  157 

classified,  169 

wanting  from  some  leaf-axils,  153 
Bulb,  axillary  (464) 
Bulbs  (461-465),  161,  168 

terminal  (464) 
Bullate  (484),  178 
Bundles,  completion  of,  in  root,  143 

development  of  secondary,  143 
Burdock  fruit  (301) 
Buttercup  akene  (344) 

leaf  (540) 

petal  and  nectary  of  (()3) 


Cactus  fruit  (281) 
Caducous,  61 
Caju,  pulp  of  (306) 
Calabar  bean  (371) 
Calamus  inflorescence  (586) 

rhizome  (452) 
Calcar  (65),  58 
Calcaria,  69 

Calesium  fruit  (279),  96 
Calisaya  bark,  mature  (427) 

young  (425) 
Callirriioe  bud  (21) 

flower  (22) 

the,  32 
Callus  (2),  25 
Calyciilorae,  219 


Calyptra,  the  (87-88),  52 
Calyx  circle,  the  double,  30 

lobes,  32,  53 

the,  32 
Cambium  circle  (422),  143 

cvlindor,  143 

<l('vel()i)ment  (422),  143 
Campanulate  (93),  54 
Camponiancsia, embryo  (400) 
Campyluspcrinous  (338),  121 
Cami)vlotropous  ovule  (244),  81 
Cancellate  (485),  178 
Cancscciit,  178 
Capillary  leaf,  179 

style  (190) 
Capitahzation,  224 
Capitate  stigma  (196),  74 
Capitulum  (578),  202 
Capsicum,  118 
Capsule  (318-328),  125 

of  moss  (599),  214 
Cardamine  (354) 
Cardiosi^ermum  (294) 

seed  (370) 
Carina  (110) 
Carinate,  64 

Carnivorous  leaves  (560,  561),  192 
Carnose,  116 
Carpel,  31 

reverted  to  leaf  (19) 
Carpels,  terminology  for  number  of,  74 
Carpology,  19 

chapter  on,  102 
Carpophore  (245,  247),  82,  120 
Carrot  fruit  (288) 
Caruncle  (380,  382),  131 
Caryophyllaceous  flower  (72),  57 
Caryopsis  (348),  123 
Cashew,  jiulp  of  (306) 
Cassia  anther  (143) 

fistula,  124 
Castalia,  metamorphosis  in  (62) 
Castanea  fruit  (284) 

leaf  (524) 
Castor-oil  seed  (380) 
Catkin  (8,  11,  15),  202 
Cauda  (115),  58 
Cautlate  anther  (133) 
Caulicle  {ca  in  Figs.  400,  etc.),  132 
Ceiba  anther  (128) 
Cell  walls,  32 
Cells,  32 

development  of  new,  106 

of  fruit,  abortion  of,  106 
Cellular  dcvel()i)m(Mit,  138 
Central  cvlinder  of  root,  141 
of  stem,  146 

placentae  (221,  etc.),  76 
Centric  embryo  (402,  403),  133 

placentae,  77 
Centrifugal  inflorescence  (584)   200 

radicle,  133 
Centripetal  anthotaxy  (577),  201 

radicle,  133 
Cei)halanthus  inflorescence  (578) 


236 


INDEX 


Cerastium  fruit  (318) 
Cercis  leaf  (528) 
Chaetostoina  stamen  (155) 
Chalaza  (241,  etc.),  80 
Chambers  (223),  76 
Channelled  petiole,  175 

venation,  178 
Checkerberry  (303) 
Chekan  leaf  (500) 
Cherry  flower  (58) 
Chestnut  burr  (284) 
Chimaphila  style  (184) 
Chondrus,  211 
Choripetalous,  53 
Chorisepalous,  53 
Chorisis,  38 

diagram  explaining  (42) 
Ciliate  (475),  178 
Cimicifuga  rhizome  (448) 
Cinchona,  false,  fruit  of  (323) 

fruit  (322) 

seed  (387) 
Cineraria,  pappus  of  (S3) 
Cinereous,  177 
Circinate,  60 

inflorescence,  200 
Circular  anther  (134) 
Circumscissile  dehiscence  (320,  325,  326), 

115 
Cirrhiferous  stem  (431),  165 
Cirrhose,  165 
Chestnut  leaf  (524) 
Cladoidia  (457,  460),  166 
Cladophylla  (457,  460),  166 
Clasping  leaf,  175,  176 
Classification  of  cryptogams,  210 
Clavate,  64 

style  (182) 
Claw  (18),  33 
Cleft  (539),  188 

perigone  (92),  53 
Cleistogamy,  96 
Clematis  bud  (122) 

leaf  (569) 
Climbing  stem,  165 
Close  pollination,  90 

sheath  (465,  B),  170 
Closed  collateral  bundle,  149 
Club  moss  (598),  215 
Coalescence,  43 
Coated  bulb  (462),  168 
Coats  of  ovule  (241,  etc.),  79 
Coccus  (330,  334),  120 
Cochlea  (353),  124 
Coelospermous  (337),  121 
Coffee  flower  (101) 
Cohesion,  43 

in  androecium,  66 

in  perigone,  52 
Cohorts,  219 

Collateral  ovules  (219),  78 
Collection  of  plants,  chapter  on,  226 
Collective  fruit,  105 
Collinsonia  leaf  (494) 
Colocynth  flower  (56) 


Color  in  attracting  insects,  92 
Columella  in  mosses,  215 
Column,  46 
Commissure,  120 
Complanate,  64 
Complete  flower,  33 
Comi)lex  inflorescence,  203 
Compositae,  pappus  of  (74-83) 
Compound  bulb,  168 

inflorescence,  203 

leaf  (548,  554),  189 

pistil  (218,  etc.),  70 
Concentric  bundle,  149 
Conceptacle  of  algae  (592),  213 
Conducting  tissue  of  style,  99 
Confluent  sutures  (131,  132),  66 
Conical  style  (181) 
Connate-perfoliate  (476),  176 
Connation,  43 
Connective  (14),  31 

modifications  of  (155-164),  68 
Connivent  anthers  (92),  66 
Consolidated  stems  (458,  460),  167 
Constriction  of  perigone  (100) 
Continuous  leaf  base  (482) 
Contracted  campanulate  (95) 
Convallaria  anther  (141) 

leaf  (526) 

rhizome  (447) 
Convolute  (120),  60 
Coptis,  petal  and  nectary  of  (64),  47 
Coriaceous  leaf,  177 
Corm  (463),  168 
Corn-seed  (369) 
Cornu,  58 
Corolla,  32 

as  a  fruit  wing  (290) 

lobes,  32,  53 
Corona  (116,  117,  150),  58 
Corrugated,  60- 
Cortex  of  stem,  145 
Corymb  (577),  202 
Costae  (527),  184 
Costate,  64 

Costinerved  (529),  186 
Cotyledons  (cot.  Figs.  400,  etc.),  133 
Coussarea  disk  (254) 
Crataegus  inflorescence  (577) 
Crateriform  (103),  55 
Creeping  stem  (445),  165 
Cremocarp  (247,  288),  120 
Crenate  (530),  187 
Crenulate,  187 
Cribrose  tissue,  142 
Cristate,  56 
Cross-polhnation,  90 

beneficial,  90 
Crowded  ovules  (232),  78 
Crown  (116,  117,  150),  165 
Cruciferous  flower,  57 
Crumpled,  60 
Cryptogamic  botan}^  19 
Cryptogams,   alternation   of  generations 
in,  207 

chapter  on,  207 


INDEX 


237 


CryptoKams,  chissifiration,  210 

comparison  with  pli;uuM-ot!;ain.s,  207 
general  characters  of,  207 
reproduction  of,  209 
the  plant  body  in,  207 
vegetation  of,  209 

Cucullate  (lOS),  56 

Cuneate  (518),  1S4 

Cupulato  stifiina  (200),  74 

Curcuma  (444) 

Curvincrveil,  1S6 

Cuspidate,  183 

Cyclanthora  anther  (134) 

Cycle  of  leaves,  196 

Cyclic  flowers,  43 

Cylindraceous  (29,  99),  54 

Cylindrical,  54 

Cyme  (584),  200,  202 

Cymose  inflorescence  (584),  200 

Cymule,  201 

Cynocrambe  embryo  (402) 

Cyperaceae  (588),  206 

Cypripedium  flower  (112) 

Cypsela  (74-80),  122 


Dalibarda  loaf  (530) 
Danais  seed  (3S6) 
Dandelion  floret  (41,  104) 

leaf  (558) 
Datura  fruit  (282) 

leaf  (523) 

ovary  of  (221,  223) 

seed  (379) 
Deciduous,  61 
Declined  corolla  (107) 
Decompound,  190 
Decumbent  stem,  165 
Decussate  (573),  196 
Defence  in  fruit,  107 
Definite  anthotaxy  (576),  200 
Deiiisce,  114 

Dehiscence  by  pores  (143,  328,  etc.),  66, 
116 

forms  of,  113 

incomplete  (318,  etc.),  115 

mechanism  of,  115 

of  anther,  65 

of  fruit  (315.  etc.),  113 
Dehiscent  fruits,  113 
Dehi.scing,  114 
Deliquescent  stem,  164 
Delphinium,  petal  and  nectary  of  (65), 

47 
Deltoid  (49S\  181 
Dentate  (n.'A),  1S7 
Denticulate,  187 
Departments  of  botanv,  18 
Dermatogon  (420),  139 

structures  from,  139 
Descending  anthotaxy,  200 

radicle,  133 
Descent  of  pollen  tube  (278),  100 


Descriptive  botany,  19 
Determinate  anthotaxy  (576),  199 

stems,  161 
Dextrorse  (125),  60 
Diadelphous  (146),  66 
Diandrous,  62 
Dianthus  (18) 
Dicldamydeous  ovules,  80 
Dichogamy,  94, 
DichotoiDovis  branching,  156 
l)ir()tvl(>(ions  (416,  etc.),  133 
DidviKimous  (151),  67 
Digitalis  leaf  (516) 

Digitateiy  veined  leaf  (527,  528),  186 
Dimerous  flower  (27),  38 
Dimorphism  (273,  274),  96 
Dinemandra  flower  (66) 
Diodia  stipules  (474) 
Dioecious  flowers,  30 
Dioeciously  polygamous,  30 
Dionacaleaf  (561) 
Diospyros  fruit  (280) 
Dipteryx,  124 

embrvo  (405) 
Direction'of  ovules  (233,  etc.),  78 
Disciflorao,  219 
Discoid,  204 
Disk  flowers,  204 

of  anthodium  (587,  c) 

the  (260-266),  83 
Dissection  of  flower,  chapter  on,  86 
Dissemination  by  edible  seed-coat.  129 

by  fixation,  129 

by  wind,  129 

provisions  for,  113 

through  seed,  129 
Distinct  i)arts,  44 
Diurnal  flowers,  93 
Divergence  of  leaves,  197 

of  ovules,  77 
Divid(Hl  leaf  (540,  559),  188 
Divisions  anil  subdivisions  of  plants,  219 
Dorsal  awns  (172) 

dehi.scence  (136),  65 

spur  (114) 
Dorsifixed  anther  (127,  129) 
Doubly  serrate  (531) 
Dried  specimens,  how  to  dissect,  89 
Drosera  leaf  (491) 
Drupe  (333),  118 
Drupelet  (305,  a),  119 
Drvmicarpus  ovule  (237) 
Ducts,  142 
Duplication,  38 
Duramen,  144 
Duration  of  leaves,  175 

of  perigone,  61 


E 


l"]c(i:\TUi(ALLY  peltate  (483) 
Eccentric  embryo  (407),  133 

])lacentae,  77 
Echites  flower  (100,  125) 


238 


INDEX 


Edible  pericarp  for  transportation  (303, 
etc.),  109 

pericarp  not  from  flower,  109 

I)()rtion  of  fruits,  origin  of,  110 

s('{>cls,  protection  to,  109 
P^ichornia  leaf  (5G4) 
Elateriuin,  dissemination  of  (314) 

fruit  (314) 
Eleutheropetalous,  53 
Eleutherosepalous,  53 
Eleutherous  parts,  44 
Elliptical  (488,  489),  179 
Elm  fruit  (287),  98,  121 
Elongation  of  internodes  of  torus  (248, 

etc.) 
Emarginate  leaf  (509),  182 
Embryo,  development  of  (364-368),  127 
132,  136 

forms  of,  134 

nourishment  of,  128 

parts  of,  132 

position  of,  133 

protection  to,  129 

requirements  of,  127 
Emergences  (148),  156 
Empirical  formulae,  41 
Enation  (63),  47 
Endocarp,  105 
Endoderm,  140 
Endophloeum,  150 
Endopleura,  129 
Endosperm,  127 
Entomophilous  flowers,  90 

cross  pollination  in,  91 
Epicalyx  (16,  21-24),  34 
Epicarp,  105 
Epicotyl,  138 
Epidermis  (422),  139 

of  stem,  145 
Epigynous  (56),  44 

disk  (254),  73 
Epigyny  (56),  44 

apparent  or  false  (59,  60) 
Epilobium  seed  (384) 
Equally  pinnate  (554),  192 
Equisetaceae,  215 
Equitant  leaves,  176 
Erect  ovules  (233),  78 
Ergot,  210 

Erigeron,  akene  of  (80) 
Eriosphaera,  pappus  of  (82) 
Erodium  (245) 
Essential  organs,  32 

protection  for,  32 
Etiolated  leaf,  193 
Eucalyptus  bud  (87) 

leaf  (504) 

fruit  (319) 
Eucharidium  seed  (383) 
Euonymus,  131 

ovule  (236) 
Eupatorium  anther  (169) 
Even  pinnate  (554),  192 
Evergreen  leaves,  175 

plants,  175 


Exaggeration  of  growth,  49 
Exalbumiiious  seeds,  128  , 
Excurrciit  stem,  164 
Exine,  99 
Exocarp,  105 
Exodermis,  140 
Exo])lil()eum,  1.50 
Ex()j)lcuni,  129 
Exsert  or  exserted,  69 
Exstipulate  leaves,  174 
Extine,  99 

Extrorse  attachment,  64 
dehiscence,  65 


Fagus  fruit  (346) 
Falcate  leaf  (504),  182 
False  septa  (220),  76 
Families  of  plants,  219 
Fascicle  of  flowers,  202 
Fascicled  leaves,  198 

roots,  160 
Female  flower  (9),  29 

gametophyte  (277),  99 
Ferns,  216 

oospore  (602),  216 
Fertilization,  90,  98 

in  cryptogams,  209 
Fibers,  142 

Fibrous  roots  (446),  160 
Fibro-vascular  bundles  of  roots,  142 

tissue  not  from  periblem,  139 
Fig  fruit  (362) 

pulp  of  (311) 
Filament  (12),  31 

forms  of,  64  ' 

Fihces,  216 

Filiform  leaf  (491),  179 
Fission,  210 
Fissured  corolla  (96) 
Fistulous  stems,  167 
Fixation  of  seed,  129 
Fixing  roots,  160 
Flabellately  nerved  (527),  186 
Flax  ovary  (224) 
Fleshy  leaf,  177 

'     roots,  160 
Flexuous  branching  (433),  155 
Floating  leaves,  195 
Floral  envelopes,  33 

leaves,  195 
Florets,  204 
Flower,  a  modified  branch  (9,  etc.,  20),  28 

cluster,  a  modified  branch  (8,  etc.), 
27 

clusters  (576-589),  199 

dissection  and  analysis  of,  86 

explained  and  defined,  28,  34 

general  nature  of,  23 

some   imperfect,   29 
Flowerless  plants,  207 
Follicle  (349),  123 


INDEX 


239 


Foramen  of  ovule,  79 

Forms,  220 

Fornicate  corolla  (119),  58 

iM.vcolate,  204 

Frankcnia  embryo  (403) 

Krasera  petal  (07) 

Fraximis  (513) 

Free  central  placenta  (230) 

parts  (47) 
Frond,  21G 

of  ferns,  216 
Frondosc  stem  (456),  167 
Fructification  defined,  102 

parts  useful  in,  103 

parts  useless  in,  103 

results  of,  102 
Fruit  and  frynaecium,  relations  between, 
104 

classification,  chapter  on,  116 
key  to,  116 
principles  of,  116 

defense  in,  107 

function  and  structure  of,   cliaptcr 
on,  102 

structviral  and   pliysioloj^ical  senses 
of,  104 

transportation  by  water,  107 
miscellaneous.  111 
prevention  of  (313),  111 
Fruits,     fixation    after    transportation, 
112 

kinds  of  (279-363) 

one-seeded  (286,  etc.) 

table  of  classes,  116 
Fruit-wings,  mor])hology  of,  108 
Fruticose  stem,  165 
P'ueus  (592,  593),  211 

sexual  organs  of  (593) 
Fugacious,  61 
P^unctions,  17 
Fungi,  210 

Funiculus  (241,  etc.),  79 
Funnel-shaped  (97),  54 
Fusiform  (442),  160 


Galbalus  (359),  126 
Galeate  (108),  56 
(!all  cone  (5) 
(Jalopina  style  (187) 
Gametes  of  Fucus  (592) 
Gametophyte,  female  (277),  99 

in  cryptogams,  207 

male  (278),  100 

of  moss  (599) 
Gamocarpous  pistil  (218),  70 
Gamopetalous,  53 
Gamoscpalous,  53 
(Jaultheria  leaf  (532) 
Gemma,  157,  209 
(i(MiiMKiti()ii,  209 
Genera,  219 


Genera  of  plants,  number  of,  219 

Generic  name,  222 

Geranium,  diagram  of  fiower  (43) 

flower  (30) 

leaf  (546) 
Germination,  conditions  for,  137 

figures  of  (416-419) 

nature  of,  137 

of  microspore  (278),  99 
Gesncria  rhizome  and  roots  (446) 
Geum  fruit  (302) 
Gibbous  corolla  (107),  56 
Glabrous,  177 
Gladiolus  conn  (463),  168 
Glands  (66-70),  47,  122 

petiolar,  175 
Glans  (345) 
Glaucous,  177 
Gl(>ditschia  leaflet  (554) 
Cileichenia,  216 
Gleof-apsa  (590) 
CJlol)ose,  54 
Globular,  54 
Glomerule,  202 
Glumaceae  (588,  589),  205 
Glumes  (588,  589),  205,  206 
Glycyrrhiza  (146) 
Gonophore  (249),  82 
Gooseberry  leaf  (539) 
Grafting,  25 
Grain  (348),  123 
Gramineae  (589),  205 
Graminology,  19 
Grape,  branching  in  (431) 

position  and  origin  of  fruit  (432) 
Grass,  flower  of  (267) 

leaf  (465  A) 

inflorescence  (589) 

like  inflorescences  (588) 
Gratiola  stamen  (167) 
Green  rose,  46 
Gregarious  plants,  91 
Grindelia,  akene  of  (78) 
Gross  anatomy,  18 
Ground-tissue  of  stele,  141 
Guaiacum  ovule  (235) 
Guarea  (147) 
Guttiferales,  219 
Gynmospermae,  219 
Gymnospermous  gynaeciiuii,  70 

ovule,  98 

pistil  (174,  175),  70 
Gymnosperms,  germination  of  (406 ~) 
Gynaecium  and  fruit,  relation  between, 
104 

chapter  on,  70 

composition  of,  29 

method  of  examining,  71 

symbols  and  fornuilae  for  structure 
of,  29 
Gynandrous  (54) 
Gynandry  (54,  55),  46 
Gynobase  (250),  82 
Gynocardia  embrvo  (401) 
Gynophore  (249,  252),  82 


240 


INDEX 


Halberd  shapod  (522),  1S4 
Hamamelis  leaf  (505,  536) 
Hanetio  seed  (375) 
Hastate  (522),  184 
Haustoria,  160 
Head  of  flowers  (578),  202 
Heart-wood,  144 
Helianthemum  style  (182) 
Heliocharis  seed  (396) 

style  (188) 
Henbane  fruit  (363) 

seed  (377) 
Hepatica,  flower  (23,  24) 

leaf  (545) 
Hepaticae,  210 
Herbaceous  leaf,  177 
Herbs,  161 

Hermaphrodite  flowers,  31 
Hesperidium  (329),  118 
Heterochromous,  204 
Heterogamous,  204 
Heterosporous  ferns,  216 
Hexaptera  (356) 
Hibiscus  bud  (121) 
Hilum  (370,  371),  80,  129 
Hippocratea  disk  (263) 
Hippurus  flower  (25,  26) 
Hirsute,  178 
Hispid,  178 
Histology  defined,  18 
Homochromous,  204 
Homogamous,  204 
Homologies,  19 
Homologues,,19 
Homonym,  225 
Homosporeae,  ferns,  216 
Homosporous  ferns,  216 
Honey-locust  leaflet  (554) 
Hop-fruit  (292,  361) 
Horizontal  anther  (129),  63 

ovules  (234),  78 

radicle,  133 
Horn  (150),  58 
Horse  chestnut  leaf  (547) 
Horse-tails,  215 
Horticulture,  19 
Houstonia  flower  (273,  274) 
Hypanthium,  45 
Hypericum  seed  (374) 
Hypocotyl,  138 

Hypocrateriform  (101,  etc.),  54 
Hypocraterimorphous  (101,  etc.),  54 
Hypoderm  (422),  140 
Hypogynous  (47),  46 
Hypogyny  (47),  46 
Hyoscyamus  anther,  136 

fruit  (362) 

seed  (377) 


Illipe,  flower  of  (44) 
Imbricate  (123,  etc.),  60 


Iinpari-pinnate  (555),  192 
Inipcrfcction,  degrees  of,  31 
Inipres.'^ed  venation,  178 
Inci.sed  (540,  546),  189 
Incumbent  cotyledons  (412),  135 

anther  (127),  63 
Incurved  teeth,  187 
Indefinite  numljer  of  parts,  40 
Indehisccnt  fruits,  113 
Indeterminate  anthotaxy  (582,  etc.),  201 

stem,  161 
Indumentum,  177 
Induphcate  (122),  59 
Indusium,  217 
Inequilateral  leaf  (505) 

base  (521,  523),  181 
Inferior  ovary  (56),  45 
Inflorescence  leaves,  204 
Inflore.scences  (576-589),  199 
Infundibular  (97),  54 
Inga,  123 

Innate  anther  (130),  63 
Inner  lip  (111) 
Insect  visits,  94,  97 
Internode  (1) 

Internodes,  growth  of,  153 
Interpetiolar  stipules  (474),  174 
Interruptedly  pinnate  (557),  192 
Intine,  99 
Introrse  attachment,  64 

dehiscence,  65 

stigmas  (191),  73 
Intruded  leaf  base  (519),  184 
Involucre  (587,  a),  205 

defence  in  fruiting  (284),  107 
Involute,  60 
Ipomoea  (91) 

bud  (120) 
Iris  fruit  (315) 

rhizome  (451) 
Irregular  disk  (261) 

suppression,  39 
Irregularity,     antero-posterior,     charac- 
terizes development,  43 

causes  of,  43 
Isomerous,  37 


Jaborandi  leaf  (525) 
Jalap,  roots  of  (437) 
Jeffersonia  fruit  (327) 
Jugae,  192 
Juniper  fruit  (359) 
Jussiaea  fruit  (321) 


Kalmia  flower  (103) 
Keel  (110),  57 
Kefir  grains,  210 
Kelp,  211 


ISDKX 


241 


Lahiatae,  "jG 

fruit  of  (334) 
Laciniate  (540),  189 
Ladenbergia  fruit  (323) 
Lamina,  2(3 

of  petal  (18) 
Laminar  stigmas  (203-20")),  74 
Lanceolate  (496),  181 
Lance-ovate  (497),  189 
Lasioi)Ogoii,  i)ai)pus  of  (81) 
Latent  1)U(1,  lt)9 
Lateral  chorisis,  40 

primaries,  184 

style  (177,  178) 
Latli3-rus  leaf  (507) 
Laurel  flower  (103) 
Layering  (2),  25 
Leaf,  anatomical  elements  of,  173 

axil  (1),  24 

base,  relation  to  petiole,  176 

relation  to  plant  stem  (477-483), 
176 

blade,  development  of  (469) 

composition  of,  26 

cvde,  197 

.U'velopment  of  (4,  466-472),  170 

dvu'ation  of,  175 

margin  (530-537),  186 

origin  of  (4),  153 

I)arts  of  (3),  26 

regions  of  (468) 

sheath,  170 

surfaces,  172 

classified,  177 

texture,  177 
Leaflets,  190 
Leaves,  arrangement  of,  li)6 

as  climbing  organs,  195 

carnivorous,  192 

floating,  195 

modified,  192 
Lecanosperma  seed  (391) 
Legume  (350),  123 
Lenma  stem  (456) 
Lemon  (329),  118 
Lens  seed  (390) 
Lepidote,  178 
Lespedeza  leaf  (549) 
Leucothoe  corolla  (95) 
Lichen  thallus  (598) 
Lichens  (598),  213 
Ligulatc  (104),  55 

Ligule,  d(>vcloi)menl  of  (465  A),  172 
Ligulitlorate.  204 
Lily  bulb  (461) 
Limb  of  petal  (18) 

of  perigone  (94),  54 
Lindera  leaf  (501 ) 

stigma  (191),  73 
Lipped  perigones,  56 
Liriodendron  leaf  (507) 
Lobed  (543,  etc.),  188 

disk  (265) 
16 


Lobed  perigone  (97) 
Lobelia  (96,  153) 

inflorescence  (583) 
Lobing  of  carpels  (216,  etc.) 
Locelli  (138),  31 
Locellus  (14) 
Lochnera  flower  (124) 
Loculicidal  dehiscence  (315),  115 
Loment,  124 
Lonicera  leaf  (5 10) 
Lower  lip  (111),  56 
Loxopterygium  (178) 
Lycopodiaccac,  216 
Lycopodiuiu  (()04),  216 
Lyrate  (559),  192 
Lysimachia  flower  (84) 


M 

Macrosporangium,  30 
Macrospores,  29 

germination  of  (278) 
Macrosporophyll,  30 
Macrosjiorophj^te,  30 
Maculate,  178 
iMaerna  (249) 
Magnolia  anther  (126) 

diagram  of  flower  (35) 

gynaecium  (251) 
Main  root  (439),  158 
Male  cell,  30,  100 

fern,  216 

flower  (12),  30 

gametophyte  (278),  100 
Malpighiaceae  (342) 
Malva  anther  (1-31) 
Malvales,  219 

Many  serialled  ovules  (227) 
Maple  fruit  (340),  121 
Marcescent,  61 
Margin  of  leaf  (530-537) 

of  perigone,  54 
Marginal  dehiscence  (141),  65 
Martiincd  petioles,  175 
Marginicidal  dehiscence  (317),  115 
Mascagnia  fruit   (342) 
Median  chorisis,  40 
Medical  botany,  scope  of,  19 
Meihilla,  141,  146 
Medullary  rays  (421,  423),  141 

development  of  .secondary,  144 
Melon,  118 
Members,  17 
Membranaceous  leaf,  177 
Menispermum  leaf  (483) 

seecl  (397) 
Menziesia  (137) 
IMericarp  (335,  etc.),  120 
Meristem,  136 
Meristematic  tis.sue,  136 
Merten.sia  (118,  119) 
Mesoearp,  105 
Mesophloem,  150 


242 


IDDEX 


Metamorphosis,  46 
Microscopes  for  dissecting,  86 
Microscopical  botany,  IS 
Microsporangium,  30 
Microspore,  development  of,  05 

germination  of  (278),  99 

structure  of,  99 
Microspores  (14),  30 
Microsporophyll,  30 
Microsporophyte,  30 
Micropyle  (241,  etc.),  79,  129 
jMiddle  primary,  184 
Midrib  (524,  a),  184 
Millefoliate  leaf  (556) 
Mimulus  flower  (94) 
Minute  anatomy,  18 
Mitchclla  flowers  (269,  270) 
Mitranthes  (88) 
Mixed  bud,  169 

praefloration,  61 
Modification  of  connective  (155-164) 
Modified  leaves  (560-569),  192 

stems,  165 
Modiola  ovary  (216) 
Monadelphous  (147),  66 
Monandrous  (25) 
Monks-hood  flower  (108) 
Monocarpellary  pistil  (219,  etc.),  71 
Monocarpous,  158 
Monochlamydeous      and      symbol     for, 

33 
Monocotvledonous  stem  structure  (424) 

149 
Monocotyledons  (404),  133,  219 
Monoecious  flowers  (15),  30 
Monoeciously  polygamous,  31 
Monomerous  flower  (25,  26),  38 
Monopetalous,  53 
Monopodial  stems,  154 
Monosepalous,  53 
Monospermous  fruits  (286,  etc.) 
Monstrosities,  46 
Morphology,  19 
Moonseed  leaf  (483) 
Moss  (595),  214 

antheridium,  215 

antherozoids,  215 

archegonium,  215 

capsule  (595),  214 

development  of  sporophj'te,  215 

gametophj'te  (595),  214 

sporophyte  (595),  214 
development  of,  215 
Mosses,  214 
Mucronate,  183 
Mullein  leaf  (477) 
Multi-jugate,  192 
Multiple  fruit,  105 

primary  root,  159 
Musci,  214 

Mustard,  androecium  of  (33) 
Mycelium,  210 
Mycology,  19 
Myristica  seed  (381) 


N 


Naked  bud,  169 

flower,  33 

ovules,  80 

seeds,  129 
Napiform  (441) 
Narcissu.s  (116) 

Nectar  and  nectaries  (63,  65),  93 
Needle-shaped  leaf  (492) 
Nelumbium  torus  (252) 
Nepenthes  leaf  (560) 

seed  (392) 
Nervature,  184 
Nerves  (529) 

Netted-veined  leaves  (524,  etc.),  185 
Neutral  flowers  (268),  33 

in  attracting  insects,  92 
Nicandra  (113) 
Niederlinia  seed  (373) 
Nocturnal  flowers,  93 
Nolina  seed  (393) 
Nomenclature,  chapter  on,  222 
Non-essential  organs,  32 
Notched  apex  (507) 
Nuca  (345),  123 
Nucellus  (241,  etc.),  79 
Nucleus  sheath  (424),  150 
Nucula  (330,  334),  120 
Numerical  plan   indicated   by   diagram, 
(43),  40 

formula,  41 

symmetry,  terminologv  of,  37 
Nut  (345),  123 
Nutlet  (330,  334),  120 
Nutmeg  (381) 

section  of  (399) 
Nux  vomica  seed  (372) 
Nymphaea  leaf  (473) 


Oakesia  leaf  (480) 
Obconical  style  (183) 
Obcordate  (506),  182 
()l)lanceolate  (502),  181 
Obhque  base  (521,  523),  56,  181 

corolla  (107) 

leaf  (505) 
Oblong  (488),  179 

elHptical  (488),  179 
Obolaria  (232) 
(^bovate  (501),  181 
Obsolctely  (532),  188 
Obtuse  (511,  etc.),  183 
Ochrea,  development  of  (472),  172 
Odd-pinnate    (555),    192 
Odor  in  attracting  insects,  92 
Oenothera  (89) 

anther  (129) 

flower  (29) 
Ofi-set,  162 
Olea  flower  (31,  32) 
OUve  flower  (31,  32) 


INDEX 


243 


( )nc-fcll(«(l  anthers  (10'),  166),  6S 

( )ii(,"-lipi)0(l  roiolla  (lOf)) 

( )ii(>-s('rialletl  ovules,  78 

Onion  bulb  (402) 

Oogonia,  213 

()6si)hore,  213 

C)o.s]jore  (277) 

Oospores  in  algao,  213 

()l)aqup  leaf,  177 

Open  canii)anulate  (91) 

eollateral  bundle,  146 

perigone  (120) 

sheath  (465,  A,  etc.),  170 
Opposite  leaves,  106 
Opuntia  fruit  (281) 

stem  (458),  167 
Orange,  118 

leaf  (550,  551) 
Orbicular  leaf  (493),  180 
Organic  bodies,  characters  of,  17 

kingdom,  17 

matter,  17 
Organogeny,  19 
Organography,  19 
Organs,  17 

Ortliospornious  (335),  121 
Ortliostacliy  (573),  196 
Orthotropous  ovule  (241),  81 
Outer  lip  (111) 
Outgrowth  (63),  47 
Outgrowths  (436),  156 
Outline  of  comjjound  leaf,  179 

of  leaf,  179 
Oval  (489,  490),  179 

elliptical  (489),  179 
Ovary  (9,  10),  32 

defence  on  fruiting  (282) 

first  plan  of  structure  (219,  etc.),  76 

second  plan  of  structure  (225,  etc.), 
77 
Ovate  (494),  179 

lanceolate  (497),  189 
Ovoid,  54 
Ovule  (277,  278) 

changes  by  fertilization,  127 

connection  between  stigma  and,  99 

internal  structure  of  (277),  98 

of  gj-mnosperms,  98 

parts  of  (241-244),  79 
Ovules  (10),  31 

direction  of  (233,  etc.),  78 

forms  of  (241,  etc.),  80 

number  of,  78 

position  of,  78 

series  of,  78 

structure  of  (241-244),  79 
Oxalis  leaf  (.506) 


Paedkria  stvle  (185) 

Palate  (94),  58 

Palets,  206 

Palm  fruit,  abortion  in  (285) 


Palmate  (.548),  190 

Falmately  compound  (547),  190 

veined  leaf  (.527,  528),  186 
Palmatifid,  189 
Panicle,  203 
Paniculate,  203 
Panicum  (514) 
Papaw  (309),  118 
Papilionaceous  (1,10),  57 
Papillose,  178 

stigma  (275) 
Pappus,  the  (74-83),  51 
Parenthetical  names,  223 
Parietales,  219 

Parallel  veined  leaves  (526),  185 
Parietal  i)lacentae  (225,  etc.),  77 
Pari-pinnate  (554),  192 
Parted  (538,  546),  188 

perigone  (84) 
Passiflora  (116) 

fruit,  125 
Paullinia  ovule  (234) 
Pea-fruit  (350) 

leaf  (567) 
Peanut  (313),  112 
Pedate  (553),  191 
Pedicel  (.584,  c),  199 
Pedicularis  leaf  (538) 
Peduncle  (a  in  576  and  583),  199 
Pelargonium,  flower  of  (48) 
Pellucid-punctate  leaf,  177 
Peltate  leaf,  176 

stigma  (183,  198),  74 
Pendant  stem,  165 
Pendulous  ovules  (239),  78 
Penninerved  leaf  (524),  186 
Peniciliate  (208),  74 
Pentimerous  flower  (30),  38 
Pentapanax  ovary  (217) 
Pentstemon  anther  (132) 
Pepo  (332),  118 
Perennial  roots,  158 

stems,  161 
Perfect  flowers,  31 
Perfoliate  leaf  (480),  176 
Perianth,  33 
Periblem  (420),  139 

structures  from,  140 
Pericambium  (421),  141 
Pericarp  defined,  105 

layers  of,  105 
Perichaetium,  215 

in  moisses,  221 
Pericycle  (421),  141 
Periderm,  140 

secondary,  140 
Perigone,  33 

chapter  on,  50 

color  of,  50 

form  of  parts  of,  50 

number  of  p'iirts  of,  .50 

special  form  of,  53 
Perigynous  (57,  58),  46 
Perigyny  (57,  58),  46 
Peripheral  .'nibrvn  M()9,  410),  133 


244 


INDEX 


Perisperm,  12S 
Peristome  of  mosses,  215 
Perncttya  flower  (102) 
Persistent,  61 

leaves,  176 
Personate  (109),  57 
Petal,  parts  of  (18) 
Petaloid  appendage  (loo),  68 
Petals,  32 

Petiolar  glands,  175 
Petiole,  26 

development  of,  172 

forms  of,  175 

for  climbing  (569) 
Petrocoptis  seed  (385) 
Phanerogamic  botany,  19 
Phanerogams    compared     with     crypto- 
gams, 207 
Pharmaceutical  botany,  scope  of,  19,  20 
Pharmacognosy,  20 
Phelloderm,  140 
Phellogen  (422),  140 
Phloem-bundles  in  root  (422),  142 
Phlox  flower  (57),  46 
Phores,  S3 

Phyllanthus  branch  (460),  167 
Phyllocladia  (460),  167 
Phyllodia  (562),  195 
Phyllotaxy  (570-575),  196 

relation  to  flower-structure,  199 
Phylogeny,  18 
Physiological  botany,  18 
Physiology  defined,  18 
Phytography,  19 
Phytomer  (1),  23 

products  of  (1),  23 
Picea  fruit  (360) 
Pileus,  211 

Piliferous  layer  (416),  139 
Pilocarpus  leaf  (509,  525) 
Pilose,  178  1i 

Pine  leaf  (492) 
Pinnae,  190 

Pinnate  (549,  etc.),  190 
Pinnately  compound  (549,  etc.),  190 

veined  leaf  (524),  186 
Pinnatifid  (538,  556),  188 
Pinnules,  183,  190 
Pinus  pistil  (174),  71 
Piper  style  (181) 
Piptoptera  fruit  (290) 
Pistil,  gymnospermous,  70 

parts  of  (9,  10),  31 

the,  29 
Pistillate  flower  (9),  29 
Pitcher  plant  (560),  192 
Pith,  141,  146 
Placenta  (10),  32 
Placentae,  modifications  of.  77 
Plaited,  60 

Plantago  leaf  (481,  515,  527) 
Plantain  leaf  (481,  515,  527) 
Platypodium  fruit  (296) 
Plerom  (420),  138 

structures  from,  141 


Plumose  anther,  68 

stigma  (209),  74 
Plumule  (405,  7;^,  133 
Podophyllum  rhizome  (449) 
Pollen,  fixation  of  (275).  98 

grains  (14),  30 

development  of,  65 

tube  (278),  99 

descent  of  (278),  ICO 
Polhnaria  (140),  65 

Pollination  and  fertilization,  chapter  on, 
90 

by  birds,  93 

defined,  79,  89 
Polhnia  (135,  140),  65 
Polycarpous,  158 
Polycotyledons  (406),  133 
Polygahneae,  219 
Polygamous  flowers,  30 
Polygonatum  rhizome  (450) 
Polygonum  leaf  (519) 
Polypetalous,  53 
Polysepalous,  53 
Polystelar  stems,  150 
Pome  (308),  119 
Ponthiera  pollinia  (140) 
Poppy  fruit  (358),  125 
Pores,  dehiscence  by  (328,  etc.),  66 
Position  obscured,  42 
Posterior  side  of  flower,  41 
Potaha  style  (186) 
Potato  (446) 

Potentilla,  flower  of  (45,  46) 
Poterium  leaf  (488) 
Praefloration  (120-125),  59 
Praefoliation,  169 

Preservation  of  plants,  chapter  on,  226 
Prickly  pear  (281) 
Primary  bundles  of  stem,  146 

leaf  (466) 

root,  145,  158 

stem,  162 
Primine  (241,  etc.),  79 
Primordial  leaf  (466) 
Prismatic  perigone  (94),  54 

style  (183) 
Procumbent  stem,  165 
Produced  base  (516),  184 
Proliferation,  200 
Propagation  by  cuttings,  25 

by  nodes  (2),  25 

vegetative,  25 
Prosopis  fruit  (353) 
Protection  of  fruit,  110 

to  seeds,  110 
Proterandry  (269,  270),  94 
Proterogyny,  94 
Protonema,  214 
Prunus  flower  (58) 

leaf  (490) 
Pseudima  disk  (260) 
Pseudocarp,  105 
Psorospermum  (38) 
Psyllocarpus  fruit  (325) 
Pteridophyte,  215 


INDEX 


245 


PubciuU'iit ,  177 

Pubescent,  177 

Pulsatilla  flower  (10,  286),  32 

Pulverulent,  177 

Pulviniis,  21),  173 

Pumpkin,  US 

Punctate,  17S 

Putanien,  17!* 

Pyrene  (331),  119 

Pvrola  leaf  (489,  493) 

Pyxis  (302),  125 


QuERCUS  leaf  (543) 
Quinate.  191 


R 


Raceme  (580,  582),  202 
Rachis  (5S3  and  586) 

of  inflorescence,  199 

of  leaf  (475) 
Radial  section  of  stem  (423),  147 
Radiate,  204 
Radicle  (u  in  Figs.  400,  etc.),  133 

directions  of,  133 
Ranales,  219 
Ranunculus  akene  (344) 

leaf  (540) 

petal  and  nectary  of  (63) 
Raphe  (124.  etc.,  241,  etc.,  372.  373),  SO, 

130 
Ray-flowers,  204 
Rays  (587,  e),  204 
Receptacle  (587,  h),  204 
Reclining  stem,  165 
Rectinerved,  1S6 

Recurved-jiendulous  ovule  (240),  78 
Reduced  leaves  of  inflorescence,  205 
Reduplicate  (121) 
Regular  iluplication,  38 

suppression,  38 
Regul^ritv,  law  of,  43 
Renifonn" anther  (131),  63 

leaf  (495),  ISO 
Repand  (536),  188 
Repent  stem,  165 
Reproduction,  sexual,  29 
Resupinate  ovule  (236),  78 
Reticulate  in  special  sense  (525) 
Reticulated  leaves  (524,  etc.),  185 
Retwc  (512),  182 
Reversion  of  tvpc,  47 
Rcvolutc  (.VIL  o42).^89 
Rhamnus  (.T^fT 
Riiizoids  (599),  Hit) 
Rhizome  compared  with  root,  102 

forms  of  (147-452),  103 
Rhizomes  (447-452),  1(52 
inionil)oi(lal  (.')()()),  ISl 
]{hytid()ma,  140 
Ribbon-shaped  leaf  (4s7) 


Ribs  (527),  184 
Ricinus  seed  (380) 
Ring  bork,  140 
Ringent  (111),  57 

Root  and  stem  structure,  branching  of, 
144 

cap  (410),  139 

diapter  on,  130 

hairs  (410),,  139 

minute  structure  of,  138 
Roots  and  stems  classified,  chapter  on, 
158 

duration  of,  158 

figures  of  (437-443) 

forms  of  (441,  etc.),  160 

from  stem,  157 

functions  of,  160 
Root-structure     compared     with     stem- 
structure,  145 
Rose,  flower,  double  (59) 
single  (60) 

leaf  (486,  555) 

sepal  of  (73) 
Rosemary  leaf  t542) 
Rosmarinus  (542) 
Rotate  (92),  55 
Rotund  leaf  (493),  ISO 
Rubus  leaf  (506) 
Rugose,  178 

Rules  of  nomenclature,  222 
Rumex  (29S) 

fruit  (283,  289) 

leaf  (522) 
Ruminated  albumin  (399) 
Runcinate  (558),  192 
Runner  (445),  102 
Rupturing  fruits,  115 


Saccate  corolla  (112) 
Sagittate  (520),  184 

anther  (133),  03 
Salient  teeth,  187 
Salix,  flowers  of  (5-13) 

leaf  (3,  497) 

ovary  di.ssection  (10) 

twig  (1,  5-13) 
Salpichroa  (253) 
Salverform  (101,  etc.),  54 
Salvia  flower  (111) 

stamen  (104)  • 
Samara  (288,  etc.),  121 
Sanguinaria  anther  (130) 
San t alum  disk  (200) 
Sanvcgesia  seed  (376) 
Sai)onaria  inflorescence  (584) 
Sap-wood,  144 
Sarcina  (.-)93),  213 
Sarraccnia,  171 
Sassafras  anther  (138) 

leaf  (544) 

stamen  (70) 
Saucer-shaped  (103),  55 


246 


INDEX 


Scabrous,  178 
Scale-bork,  140 
Scalv  bud,  169 

bulb  (461),  168 
Scape  (576,  a),  199 
Scariose  leaf,  177 
Scarious  leaf,  177 
Scattered  leaves,  198 
Schizocarp  (330,  334),  119 
Scion,  25 
Sclerotum,  210 
Scorpioid  raceme  (434),  202 
Scouring  rushes,  215 
Scurfy,  177 
Scutellaria  (151) 
Scutellum  (415) 
Secondary  growth  in  stem,  146 

in  superficial  structure  of  root, 
158 

roots,  145 

stem,  162 
Secondaries  (524,  h) 
Secund  branching  (434) 

leaves,  155 
Secundine  (241,  etc.),  79 
Sedge  leaf  (465,  B) 
Sedum,  flower  of  (47) 
Seed,  dissection  and  examination  of,  135 

appendages  of  (384,  etc.),  131 

chapter  on,  127 

coats,  129 

figures  of  (369-415) 

leaves,  132 

method  of  examination  of,  135 

parts  of,  128 

\'itality  of,  136 
Seeds,  provisions  for  scattering,  113 
Seedless  plants,  207 
Sepals,  32 
Septa,  32 

abortion  of  (230),  76,  106 

development  of  new,  106 

of  fruit,  abortion  of,  106 
Septate,  191 

Septicidal  dehiscence  (316) 
Sericeous,  177 
Series  of  plants,  219 
Serrate  (533),  187 
Serrulate  (535),  187 
Sessile  leaf  (478) 
Sexual  reproduction,  29 
Sheathing  leaf  (162) 
Shrub  defined,  165 
Siccose,  116 
Sickle-shaped,  182 
Sicyos  anther  (139) 
Sidalcea  (149) 
Sieve  bundles  in  root  (422),  142 

tissue,  142 

tubes  (422),  142 
Sigmoid  calyx  (106),  56 
Silene,  vertical  section  of  flower  (72) 
Silicic  (353-357.,  121.  125 
Silique  (254),  125 
Simple  fruit,  105 


Simple  pistil  (219,  etc.),  71 

stems,  164 
Sinapis,  androecium  of  (33) 
Single  and  double  flowers  (59,  60) 
Sinistrorse  (124),  60 
Sinuate  (536),  53,  188 

disk  (263) 

perigone  (91) 
Sinuous  anther  (139),  64 
Sinus,  32 

Siphocampylos  fruit  (328) 
Skunk  cabbage  inflorescence  (585) 
Sleeping  and  awakening  of  flowers,  93 
Smilax  leaf  and  tendril  (565),  167 
Solanum  (92),  220 
Solidago  leaf  (478,  496,  502) 
Sohd  bulb,  168 
Sophora  fruit  (352),  124 
Sori,  217 

Spadix  (585,  586),  202 
Spathe  (585),  205 
Spathyema  inflorescence  (585) 
Spatulate  (503),  181 
Species  of  plants,  number  of,  219 
Specific  name,  222 
Spermatophyta,  219 
Spigelia  (97) 
Spike  (583),  202 
Spikelet  (347,  589),  123,  206 
Spines  (453),  165 

becoming  branches  (454) 
Spinulose  teeth,  188 
Spiral  leaf  arrangement  (571),  190 
Sporangium,  30 
Spore  germination  in  cryptogams,  101 

mother  cells,  65 
Sporophyll,  30 
Sporophyte,  30 
Spur  (65),  58 
Squash  androecium  (148) 
Staeha  fruit  (326) 
Stamen-circle,  the  single,  43 

column,  46,  66 

parts  of  (12,  14),  31 
Staminate  flower  (12),  30 
Staminodia  (38,  44),  62 
Standard  (110),  57 
Stele,  141 

differentiation  of  its  cells  (421) 

secondarv  growth  in,  142 
Stellaria  flower  (39,  40) 
Stem  and  root  structure,  chapter  on,  136 

composition  of,  26 

extensions  and  appendages  of,  chap- 
ter on,  153 

structure  compared  with  root  struc- 
ture, 145 
nionocotyledonous  (424) 
Stems  and  roots  classified,  chapter  on, 
158 

classification  of,  161 

duration  of,  161 

order  of  development,  162 

subterranean  (444-452),  162 
Sterile  filament  on  anther,  62 


INDEX 


247 


Stigma,  forms  of  (191-215),  7.S 

papillose  (275),  97 

position  of  (191-215),  IS 

size  of,   proportional   to   number  of 
ovules,  73 
Sligmatophyllon  (206) 
Stipellae  (475),  175 
Stipulate  leaves  (474,  475),  174 
Stipule,  26 
Stipules,  development  of  (471),  171 

forms  of,  173 
Stolon,  162 
Stone-fruit,  118 
Storage  roots  (441-443),  160 

stems,  168 
Stramonium  leaf  (5231 

seed  (379) 
Strap-shaped  (104),  55 
Strawberry  (304) 

calyx  (36) 

plant  (445) 
Strigose,  178 
Strobile  ^360,  361),  126 
Strophanthus  seed  (388) 
Strophiole  (374),  130 
Structural  botany,  18 

units,  modifications  of,  26 
Strychnos  tendril  (4551 
Style  (9),  32 

forms  of,  72 

position  of  (177,  etc.),  72 
Subgenera,  219 

families,  219 

petiolar  bud,  157 
Subterranean  roots,  160 

stems,  162 
Subulate  (499),  181 

style  (188) 
Succirubra  bark  (426) 
Succowia  (357) 
Succulent  leaf  (169) 
Sucker,  162 
Sucking  disk  (459) 
Suffruticose  stem,  165 
Superior  calyx  (56),  45 

side  of  flower,  41 
Supernumerary  bud,  169 
Suppression,  38 
Supra-axillary  bud,  169 
Suspended  ovules  (235,  237),  78 
Surfaces  of  leaf  classified,  177 
Suture  of  anther,  65 
Sword-shaped  leaf  (504) 
Syconium  (362),  125 
Symbiosis,  213 
Symmeria  ovule  (233) 
Symmetrical  Hower  defined,  37 
Sympodial  stems  (428-132),  154 
Synandrium.  66 
Svncarpous  fruit,  105 

pistil  (218,  etc.),  70 
Syngenesis,  38,  44 
Synpetalous,  .")3 
Synsepalous,  53 
Systematic  botany,  18 


Tabkrn.xemont.vna  anther  (133) 
Tail  (115),  58 
Taka-diastase,  210 
Tamarind,  119 

origin  of  pulp  (317) 
Tanacetuni,  ak^ne  of  (75) 
Tangential  section  of  stem  (423),  147 
Tapering  (514),  183 
Tap-root  (439),  158 
Taraxacum  floret  (41,  104) 

leaf  (558) 
Taxus  pistil  (175) 
Tegmcn,  129,  131 
Tendril  of  grape,  origin  of  (431) 
Tendrils  from  branches  (455),  160 
Teratology,  47 
Terete,  64 
Ternate  191 
Tertiaries  (524,  c) 
Testa  (376,  etc.),  129,  130 
Tetrad,  65 

Tetrad vnamous  (33),  67 
Tetramerous  flower  (29),  38 
Tetraplasandra  ovary  (218) 
Thalamiflorae,  219 
Thalamus,  33 
Thallophyta,  210 
Theca  (14),  31 
Thecaphore  (9),  31 
Theobroma,  petal  of  (71),  38 
Theoretical  formulae,  40 
Thorns,  165 

Thread-shaped  leaf  (491),  179 
Throat  of  perigone  (94),  54 
Thvrse,  203 

Tig'er  lily  bulblets  (464),  168 
Tilia  flower  (34,  37) 
Tissue  development,  136 
Tobacco  seed  (378) 
Tococa  leaf  (568) 
Tomato,  118 

anther  (142) 
Tomentellate,  178 
l'(jinentosc,  178 
Toothed  perigone  (102) 
Torsion  (49-53),  42 
Torus,  chapter  on,  82 

the  (16,  23,  24),  33 
Transportation  of  fruit,  107 
Transverse  section  of  stem  (423),  147 
Trape/.oidal,  181 
Tree  defined,  165 
Tribes,  219 
Triadelphous,  66 
Trichomes,  156 
Trifoliolatc  (548).  191 
Trifolium  leaf  (548) 
Trijugate,  192 
1'rimerous  flower  (28),  3S 
Trimorphism,  96 
Trinomials,  223 
Tri-j)innate  (5.56).  192 

ternate,  192 


248 


INDEX 


Trumpet-shaped,  54 
Truncate,  182 

stigma  (197),  74 
Tube  of  perigone  (94),  54 
Tubercles  (437),  IGO 
Tubers  (440),  161 
T-ufted  leaves,  198 
Tulip  (576) 

Tunicated  bulb  (462),  168 
Twining  stem,  165 
Two-lipped  corolla  (111) 
Two-senallod  ovules  (219) 
Typical  flower  and  modifications,  36 


ULMTJsleaf  (511,  531) 
Umbel  (579;,  202 
Umbellule,  203 
Unicellular  plants,  208 
Undershrub,  165 
Undulate  (537),  53,  188 

perigone  (91) 
Unequal  leaf  (505) 
Unequally  pinnate  (555),  192 
Unguiculate,  33 
Unguis  (18),  33 
Unifoliolate  leaf  (551),  190 
Upper  lip  (111) 
Urceolate  (102),  54 
Urena  (330) 
Urn-shaped  (102),  54 
Utricle  (341),  121 


VAcriNiUM,  ovary  of  (222) 

Valerian  fruit  (293) 

Valvate  (123),  59 

Valves  of  fruit.  113 

Valvular  dehiscence  (138),  66 

Vanilla  flower  (54) 

Varietal  name,  224 

Varieties,  220 

Vegetable  sulphur,  216 

Veinlets,  184 

Veins,  184 

Venation.  184 

Venus's  fly-trap  (561),  193 

Ventral  dehiscence  (142),  65 

Ventricose  corolla  (111),  56 

Veratrum  flower  (28) 

Verbascum  leaf  1,477) 

Verbesina  fruit  (295) 

Vernation,  169 

Vernonia  floret  (271) 

Versatile  anther  (129),  63 

Vertical  extension  by  branches  (431) 

Verticil,  196 

Verticillate,  196  ^/ ^ 


141 

Vexillum  (110),  57 
Viburnum  inflorescence  (268) 

leaf  (534,  535) 
Villaresia  ovary  (177) 
Viola  anther  (171) 

pedata  leaf  (553) 
Violet  leaf  (519) 
Virgin's  bower  leaf  (569) 
Viscaria  (248) 
Vitality  of  seeds,  136 
Vittae  (335,  a),  120 


W 


Watermelon,  origin  of  pulp  (312) 
Water  lily,  metamorphosis  in  (62) 
Wedge-shaped  (518),  184 
Wheel-shaped  (92),  55 
White  oak  leaf  (518) 
Whorl,  196 
Whorled  leaves,  196 
Wild-cherry  leaf  (490) 
Willow  cone  (5),  27 

flowers  of  (5-13) 

leaf  (3,  497) 

ovary  dissection  (40) 

twig  (1,  .5-13) 
Wind-transportation  of  fruit  (287,  etc.), 

98 
Winged  petiole,  175 
Wings  (110),  57 
Winter  annuals,  158 

bud,  161 
Witch  hazel  leaf  (505) 
Wood-bundles  in  root  (422),  142 

fibers,  142 
Woody  roots,  160 
Wyethia,  akene  of  (77) 


Xanthium,  122 

Xanthoceras  disk  (264) 

Xerophytic,  194 

Xylem  bundles  in  root  (422),  142 


Yeast  plant,  210 
Yew  pistil  (175) 


Zea  style  (190) 
Zinnia  fruit  (291) 


60 


T"^  /        N.  MANCHESTER. 


INDIANA 


